PEPVEET TL trt yee wii 3 1924 084 969 934 VETERINARY PARASITOLOGY VETERINARY PARASITOLOGY REGINALD H. SMYTHE, M.R.C.V.S. CHICAGO ALEX. EGER IQII VET ae gis AB SeS a PREFACE OF late years, owing to the increased attention paid to the study of parasitology in our veterinary schools, there has arisen a need in our literature of a textbook, which, although dealing more or less fully with the more common parasites of the domesticated animals, shall yet be concise and of a handy size. It has been the aim of the author to fill the gap with a volume which, while covering the course laid down for the student, shall be at the same time of practical value to the veterinarian as a book of reference. With this end in view, the symptoms produced by the various para- sites have been fully described, together with the latest methods of treatment, and, where possible, prescriptions have been inserted. REGINALD H. SMYTHE. ALBANY Roap, REDRUTH. November, 1910 CONTENTS CHAPTER I PARASITES AFFECTING THE SKIN PAGES Vegetable parasites—Ringworm—Ringworm in the horse—" Favus in sucklings—Ringworm in the ox—Ringworm in the dog and cat—Diseases of the skin caused by animal parasites—Psoric acariasis (mange)—Mange in horses— Mange in cattle—Mange in the dog—Mange in cats— Follicular mange—Mange in sheep—Sheep scab—Non- psoric acariasis — Phthiriasis— Pulicide — Cutaneous filariasis—Summer sores—Dracontiasis—Diptera affect- ing the skin—Culicide Simuliide—Brachycera—Taba- nide—Muscide—(stride—Hippoboscide as 1-49 CHAPTER II PARASITES OF THE ALIMENTARY TRACT Vermes—Annelida—Helminthes—Cestodes—Trematodes — Nemathelminthes — Ascaride — Oxyuride — Filariide Trichotrachelide — Strongylide — Acanthocephala — Parasites inhabiting alimentary canal of the horse— Parasites inhabiting the alimentary canal of the ox— Strongyles inhabiting the alimentary canal of cattle, sheep, and deer—Protozoa inhabiting the intestine— Tapeworms in sheep—Parasites inhabiting the ali- mentary canal of the pig—Intestinal parasites of the dog and cat .. 2% ie de a4 a 50-96 vii viii CONTENTS CHAPTER III PARASITES WHICH INVADE THE LIVER PAGES Linguatula—Tenia cysts—Distomiasis ee a 97-105 CHAPTER IV PARASITES OF THE RESPIRATORY TRACT Bronchial strongyles—Parasites inhabiting serous mem- branes—Hematozoa—Parasites of muscle and con- nective tissue—Measles—Trichinosis—Parasites affect- ing the eye 106-123 APPENDIX .. 124-125 INDEX 126-129 15. 16. 17. 18, 19. 20. 21. 22. 23. 24. 25. 26. 27: 28. 29. LIST OF ILLUSTRATIONS TRICHOPHYTON TONSURANS SaRcoPTEs Equi: DorsaL SURFACE Psororpres Egut (MALE): DorsaL SURFACE - . SYMBIOTES Egui (MALE) : VENTRAL SURFACE AcaRus DEMODEX FOLLICULORUM . HExapoD LARVA oF RHIPICEPHALUS ANNULATUS . IxopEs REDUVIUS . TRICHODECTES SCALARIS . H@&MATOPINUS MACROCEPHALUS Estrus Egui . LARVA OF GASTROPHILUS EQUI . HEAD OF T#NIA PERFOLIATA . T#NIA PERFOLIATA . HEAD oF TANIA PLICATA Heap or T#n1a MAMILLANA ASCARIS MEGALOCEPHALA OxyuRIS CURVULA Heap oF T#NiA EXPANSA HEAD oF T#NIA ALBA HEAD oF T2#NIA DENTICULATA HEAD AND SEGMENTS OF T#NIA FIMBRIATA - TZNIA SERRATA Tania SERRATA: Hooks T2NIA MARGINATA | Tania ECHINOCOCCUS - Tania CUCUMERINA BoTHRIOCEPHALUS LATUS Distomum HepaTicumM: LIVER FLUKE LINGUATULA TNIOIDES PAGE 13 14 15 22 34 35 38 39 48 57 61 61 62 62 63 70 73 73 74 82 86 87 89 go 92 92 100 107 VETERINARY PARASITOLOGY INTRODUCTION A PARASITE may be defined as a living organism which, for the purpose of obtaining nourishment, passes the whole or a portion of its existence upon or within another living organism. Parasites may be divided into two main classes : 1. Animal parasites, or zoo-parasites. 2. Vegetable parasites, or phyto-parasites. Of these, the latter are by far the smaller group, and all those which affect the domesticated animals belong to the fungi. They are a series of very low forms of plant-life, and their common mode of reproduction is asexual, by means of spores. The Dermatomycoses, which embrace the three chief species of ringworm, as found in the domesticated animals, may be taken as the type. Animal parasites are all obligatory at some period of their existence, but in many the host is only required during a portion of the life of the parasite, and so one speaks of “ fixed parasites ’’ and “‘ transitory parasites.” The Tzniz serve as an example of the former, as they are unable to maintain their existence apart from their host, while of the latter the Gstride, the bot-flies, are typical. Transitory parasites are chiefly confined to those parasites whose habitat is on the surface of the skin, or within or near the natural openings, such as the xi xii INTRODUCTION mouth and nose. In other words, they are ecto- parasites, or, as they are sometimes called, Epizoa. Fixed parasites are chiefly endo-parasites, or Entozoa —that is, they live in those cavities which communicate with the exterior, such as the intestines, lungs, and bronchi, or sometimes in closed cavities, as the blood- vessels or peritoneal sacs. The endo- parasites ate degenerate, but possess great vitality and enormous fertility, and are often hermaphrodite. The majority of the Entozoa require more than one host in which to pass their life-history, and these are usually of different species. The host in which they reach the adult reproductive stage is spoken of as the “ultimate’”’ or ‘‘ definitive host,’ while the former host is known as the “intermediate host.’’ The cycle commences with ova or larve which have gained the exterior. These invade the ‘‘ intermediate host,’ within which they undergo certain changes in their develop- ment, and are then taken in by the “ ultimate host,” in which they complete their process of development and reach the adult stage. As a general rule each mammal has its own particular parasites, but some of the ecto-parasites are capable of existence on several animals. Hence, the mange para- sites of horses may affect man, but their vitality is thereby greatly impaired, and they are unable to exist any length of time away from their natural host. Entozoa may occasionally invade a host of a different species. For instance, Trichina of the pig sometimes invades the muscles of man, while Bothriocephalus latus, a tapeworm found in man, in some countries can live in the dog. Etiology. — The old theory which was supposed to account for the presence of parasites was that of spon- taneous generation, but with the advancement of science and research, this theory has been discarded. The great INTRODUCTION xili majority of parasites are acquired by transmission from other animals, either by mediate or immediate con- tagion, though a few may be hereditary—that is to say, transmitted to the young animal through the genital organs of the mother. The piroplasms and trypano- somes are examples of this method of infection. Mange parasites and lice are transmitted by actual contact or by mediate contagion, as from harness, grooming utensils, or even from attendants. In the case of a great number of parasites, ova or embryos from one animal may be ingested by another, or, as in the case of Hvpoderma bovis (the warble-fly), the eggs may be de- posited on, or in some cases under, the skin of the host. Some parasites, such as leeches, and probably some of the Nematode worms, may be taken in with the drinking-water. It may be taken for granted that an animal possesses a certain degree of immunity against parasitic invasion, dependent upon the general constitution and state of health, and upon the condition of the various organs. Worms usually infest the intestines of an animal already in low condition, and in which the intestinal tract is already probably deranged and weakened. In a similar manner lice and mange Acari infest the skin of an emaciated animal or one suffering from some chronic debilitating disease. Tuberculous cattle in the stage of emaciation are usually affected with lice, and it is more reasonable to suppose that emaciation and loss of tone afford an opportunity for the parasites to take up their abode than that they infect a healthy animal and produce these symptoms. It cannot be denied that in many cases, after the invasion of the particular parasite, the previous symptoms are exaggerated, and sufficiently so sometimes to bring about death. Sclerostomum armatum and S. tetvacanthum of the horse afford good evidence of this. : xiv INTRODUCTION Environment and season have a direct influence on the prevalence and vitality of parasites. A wet season predisposes to fluke disease, providing the locality is one in which flukes and their intermediate hosts (L. ¢runcata- lata) are already present. Effects of Parasites.—Parasites produce their effects in various ways, according to their position and nature. In the bowel, worms may produce anemia through draining away blood from their host, and even per- foration of the bowel-wall may result, with consequent peritonitis. Flukes at the time of migration act mechanically by blocking the bile-ducts, and so jaundice and ascites result. Strongyles are common in the respiratory tract of young ruminants, and produce bronchitis and even pneumonia. Some parasites produce toxins, which exert a poisonous effect on their host, but these are rare. Ascaris mar- ginata has been credited with the power of excreting a toxin which produces fits in the dog, but this is very doubtful, and it is more probable that the actual cause is reflex action, set up by irritation of nerve-endings in the bowel. Ascarides also may produce mechanical obstruction of the bowel by grouping together into bundles or balls. Tenia cenurus will serve as an example of a parasite which produces its effects by reason of the position it takes up in the host’s body. The Cenurus cerebralis, which is its cystic stage, exists in some part ‘of the cere- brum or cerebellum, and thereby produces nervous symptoms, which vary according to the exact site. ZOO-PARASITES. | Protozoa, _ | | lL. Rhizopoda. Flagellata, Sporozoa. Annelida. | Ameeba. Trypanosomes. - ~ ee | Coccidia. Sarcosporidia (Hemosporidia. Platodes. (Miescher’s tubes). Piroplasms. Cestodes. Tre [. ects Treniz. Dipylidium. Anoplocephalinz. Distomum. Amphistomum, G: “ Ascaridee. Oxyuride. Filariidee, | Ao a, | Filaria, Spiroptera. Eustrongyles, Vermes, Arthropoda. | = | Helminthes. Arachnida. Insecta. Linguatula. Acarina. | ee Nemathelminthes. l ] ] | | Pentastoma. Linguathla. Ixodidz. Trombidiide. reoptide. Demodecide. Diptera. Hemiptera. | Pa | L Nematodes. Acanthocephala. Rhipicephalus, Ixodus. Sar Psoroptes. Symbiotes. Aptera. | | Aphaniptera. Nemoceri Brachycera, Heteroptera. Pediculinz. Betti | Bilharzia. Culicide. Pedichtidee. Ricinide. i 1 | | Strongylidz. Trichotrachelide. Pediculus. Phthirius. Hzmatopinus. | | i | | | | : , | Strongyles. Sclerostomes. Trichocephalus. Trichinz, Tabanidz. Muscidze, stride. Hippoboscidze, Trichodectes. | i Sarcophaga. Lucilia. (To face page 1. CHAPTER I PARASITES AFFECTING THE SKIN VEGETABLE PARASITES RINGWORM THE vegetable parasites affecting the skin of animals are a series of very low forms of plant-life, and are usually classed with the moulds. The skin diseases they produce are grouped together under the term “ ringworm,” but are caused by variations of the same fungus. The differentiation between them is only marked as regards their mode of reproduction, though each shows a prefer- ence for some particular culture medium. They are all parasitic fungi, and chiefly attack the epidermis, at the expense of which they maintain their existence. Several observers have stated that they are capable of sapro- phytic existence, quite apart from an animal host, and thus infection may take place without any direct con- nection with an affected animal. It is certain that their vitality is exceedingly great, and-they show a marked resistance to desiccation, and various experimenters have found that scabs or crusts will remain active and produce ringworm in an animal after having been re- moved from another animal for a period of from one to two years, The common mode of reproduction among the skin fungi is asexual, by sporulation. The spores give rise I 2 VETERINARY PARASITOLOGY to much-branched filaments, known as “ hyphe.”’ These intermingle and produce a matted mass, which is known as a “‘ mycelium.” Besides these, there are other branches given off, usually at right angles, which have a reproductive function, and which bear at their extremity spore-cases known as “sporangia.” Each sporangium contains a large number of minute spores. In some cases the spore-case contains only one spore, and is then known as a “ conidium.”’ A modified form of sexual reproduction is seen in the Ascomycetes, in addition to the ordinary asexual repro- duction. Two hyphe come together, and a process takes place known as conjugation, and results in spore formation afterwards. The spore-case is known as an ““ascus,” and contains eight spores, four of which would be seen in a longitudinal section and two in a transverse section. There are three chief species of skin fungus seen in our domesticated animals. These are, respectively, Tri- chophyton, Microsporon, and Achorion. 1. Trichophyton.—The mycelium consists of fine elon- gated tubes, showing a single contour. They may be simple, segmented, or dichotomously branched. The hyphz twine round the hairs, forming a whitish mass at the roots, and also penetrate into the interior. The result is that the hairs become rough, often split, and finally fall out or are cut across. The spores are spherical or elliptical, and are con- tained inside the older segments, which they almost entirely fill. They are so numerous as to form a chain, and often obscure the hyphz themselves, when a scraping is examined microscopically. On agar-agar Trichophyton develop a green culture. The skin fungi will grow on most media, providing a little glucose is added. Both this variety and Achorion liquefy gelatine. PARASITES AFFECTING THE SKIN 3 2. Microsporon._-In addition to ordinary spore forma- tion within the segments, Microsporon develops lateral reproductive branches, which bear conidia. 3. Achorion.— The mycelium consists of much- branched hyphz, which may or may not be segmented, and are sometimes straight and sometimes curved, They break up into spores when ripe, and hence, when examined microscopically, one sees between the branches of the mycelium large numbers of triangular, round, or oval spores. The variation in shape depends upon their degree of development. The whole growth forms a crust of a yellowish colour, and is in reality a pure culture of the fungus. In order to examine these growths microscopically, one proceeds by scraping the deeper parts of the crusts and soaking the material obtained in diluted liq. potassz, in order to dissolve out the fat. The prepara- tion is then placed on a warm slide, and stained with lactic blue. It is best mounted in glycerin or glycerin jelly, and a cover-glass applied. Ringworm occurs chiefly in two forms—the Tricho- phyton and the Achorion form, which is known as favus, or honeycomb, ringworm. There has been much dis- cussion as to whether these are distinct parasitic affec- tions, or whether they both are variations of a common type. In the skin lesions marked differences between them are apparent, for while the eruption produced by Trichophyton is widely dispersed and rounded in shape, that produced by favus is yellow, and occurs in the form of large crusts. Predisposing Causes.—As in most other parasitic diseases, dirty surroundings and a debilitated condition of the host afford increased facilities for the growth of the fungus. Old animals are less commonly affected. Certain sheds on farms where the disease is prevalent convey infection to each fresh batch of calves, owing 4 VETERINARY PARASITOLOGY to the walls and uprights being used for rubbing against, and so the disease is propagated from year to year. Among horses, grooming utensils, more particularly curry-combs, act as sources of mediate contagion. . Rats and mice suffer from a variety of favus, which is very contagious to cats and dogs, in which the lesions develop on those portions of the body which come in contact with the rodents. Hence it is common to find crusts on the paws and around the head, particularly on the ears. Ringworm in the Horse. The commonest varieties met with are Trichophyton and Microsporon. Favus in horses is rare. The disease is seen chiefly in foals and young horses, but older animals are not uncommonly affected. The eruption occurs in the form of small rounded patches on the trunk, particularly on the croup and shoulders, and also upon the head and neck. The hair on these first becomes erect, then matted. The parasites attack the hairs, which break off level with the skin, and fall out, cemented together by a scab. The bare patches left are of a slaty-grey colour, and covered with silvery scales. At first they are the size of a sixpence or a shilling, but spread from the periphery, and may attain the size of a two-shilling-piece, or become even larger still. After recovery, the hair covering the patches is at first darker in colour. Several varieties of trichophytosis are seen in horses. Trichophyton mentagrophytes affects the hair-follicles, and so, in addition to the bare patches described, one sees small pustules, which are quite visible after removal of the scab. The patches grow larger than in the variety just described, and may attain the size of a crown-piece. Prognosis.—Trichophytosis in the horse runs a benign PARASITES AFFECTING THE SKIN 5 course, and produces no systemic disturbance, and is spontaneously curable, providing cleanliness is main- tained. In dirty, emaciated, half-starved animals it tends to remain. Trichophytosis is transmissible from horses to the attendants, and produces serious lesions on unprotected parts, such as the arms and face. It is also transmissible to cattle. Favus in Sucklings. This is a rarer condition, and is characterized by the presence of scabs or discs of a greyish colour externally, Fic. 1.—TRICHOPHYTON TONSURANS, and which are yellow in their deeper parts—that is to say, when the surface is scratched away. They seldom exceed 3 inch in diameter, and are confined chiefly to the region of the head; but a few isolated crusts may appear on various parts of the abdomen, and more particularly on the quarters. Favus is never trans- mitted to other animals. 6 VETERINARY PARASITOLOGY Ringworm in the Ox. The only variety affecting cattle is a trichophytosis, and it rarely affects animals over one year old. The lesions are found in the region of the head, particularly round the eyes and on the neck and shoulders. They assume the form of more or less rounded patches of a silvery grey colour, ranging from I to 3 inches in diameter in the early stages, but later become larger by conflu- ence, until the whole of the head and neck may even- tually be left bare. The follicles are affected at the same time, and give rise to small pustules, which raise the scab, and this, if removed, leaves a raw bleeding surface exposed. Prognosis.—Except in weak undersized calves, tricho- phytosis is spontaneously curable, and runs its course usually in from one to three months. It is easily trans- mitted to the attendants, and produces much more serious lesions. Occasionally the mouths of sucking calves become affected, and this form is very difficult to treat successfully, owing to its position. Ringworm in the Dog and Cat. Both Trichophyton and Microsporon affect the dog, but more commonly a favus (Odspora canina). Tricho- phytosis appears in the form of round, sharply defined areas, usually of the size of a shilling, starting at the head, and extending to the body, particularly to the skin of the chest under cover of the elbows. These bald spots are often covered with dirty grey scales, but often there is no sign of inflammation. Asa result of scratch- ing, they may become raw, and a little blood may exude. As they get older, the patches become lighter in colour, and gradually revert back to the original colour of the skin. The variety of favus attacking the dog and cat is known as the Achorion Quinckeanum. It affects chiefly PARASITES AFFECTING THE SKIN 7 the tips of the ears, the paws, and the face, and is seen more often in kittens and rather seldom in old cats, The lesions take the form of lemon-yellow crusts, which are at first firm and moist, but later become dry and inclined to crumble on pressure. Their appearance is very characteristic. Therapeutics —In treating a case of ringworm, as in other parasitic skin diseases, it is first necessary to isolate the affected animals, and to provide fresh litter. All clothing and grooming utensils should be thoroughly disinfected. Horses suffering from trichophytosis should have the affected parts thoroughly washed with hot soda-water. When quite dry, they should be dressed with para- siticides. If the areas are small in extent, nothing is better than ung. iodi, or even half-strength tinct. iodi. Formalin 4 per cent. in water, to which 5 per cent. glycerin has been added, is useful. Lysol, creolin, naphthol, or salicylic acid may be used. In calves, where the areas affected are large, a dressing composed of sulphur, combined with ol. picis and an alkali in oil, is best, such as the following : B Sulph. flores. .. Se oy .. 3iv. Liq. potasse .. be a .. Bij. Ol. picis a i es .. Bij. Ol. rapii ie me ad O.j. M. Fiat lin. In dogs and cats preparations of iodine are probably best, and care must be taken to prevent access to mice and rats, which may have introduced the disease. The treatment of favus is similar to that of trichophy- ‘tosis. The crusts should be first removed, and the affected areas well washed, after which any of the para- siticides mentioned may be used. In treating ringworm it must be remembered that the patches extend from 8 VETERINARY PARASITOLOGY their edges, and hence the dressing used should be applied beyond the apparent margin. The most hopefu! sign of recovery is the appearance of a smooth crop of fresh hair. DISEASES OF THE SKIN CAUSED BY ANIMAL PARASITES. PSORIC ACARIASIS (MANGE). Mange is the name given to that condition of the skin produced by the presence of mange-mites, which belong to the Acarina. It is a very contagious disease, as the parasites can leave the host and pass on to another animal with ease. The Sarcoptide are small round or oval parasites, with a striated cuticle (usually transversely), and the majority are barely visible to the naked eye. When adult, each possesses four pairs of legs, composed of five segments, and terminating in suckers, used in walking as prehensile organs, and known as ‘‘ambulacra.”’ They are each carried on a stalk, known as the “‘ pedicle.” In addition, there is usually a long bristle at the end of each terminal segment. The body is short, thick, and non- articulated, the head, thorax, and abdomen being united together into one piece. The head bears a projection known as the ‘“‘rostrum.” This is the buccal organ, and is composed of two prominent trophi, the jaws being scissor-like in some, and serrated, or even arranged in the form of stiff bristles, in others. They have no eyes. The males are less numerous and smaller than the females. Many varieties bear copulatory suckers on their posterior extremities. Life-History.—The mange parasites pass their lives either on the skin or in burrows made beneath the surface. The ovigerous female lays from twenty to PARASITES AFFECTING THE SKIN 9 twenty-four oval-shaped eggs in one batch, each con- taining an embryo, just visible when examined micro- scopically. About a month after the completion of this function the female dies. Ina week each egg hatches out a larva, which possesses only six legs, and hence is termed the “ hexapod larva.” It possesses no sexual organs. In its turn the larva becomes a nymph, with eight legs, but is still asexual: but in a few more days it develops generative organs, and becomes a sexually adult parasite. The whole process, from the egg stage to the adult, takes about three weeks. The males crawl about, and each, after fertilizing a number of females, dies in about six weeks. The mange parasites can exist away from any animal host for a period of from two weeks to two months. Rugs and grooming implements remain infective for three weeks or longer, but on damp walls and partitions the parasites may remain active for two months. In warm surroundings and in sunlight they become more active. There are four chief varieties of mange parasites, viz. : Sarcoptes, producing sarcoptic mange ; Psoroptes, pro- ducing psoroptic mange ; Symbiotes, sometimes known as Chorioptes, producing symbiotic or chorioptic mange ; and Demodecide, producing follicular or demodectic mange. 1. Sarcoptes.—These are the smallest of the mange parasites, and are burrowers—that is, they live beneath the surface of the skin in tunnels, which they bore out. They usually reach the rete Malpighii, where they live on lymph. The body is rounded, as is also the rostrum. The legs are short, and bear simple unsegmented long pedicles. These are absent in the third pair in the male, and in the third and fourth pairs in the female. The posterior two pairs of legs are ventrally placed and 10 VETERINARY PARASITOLOGY hidden under the body, so that from the dorsal aspect only two pairs are visible. 2. Psoroptes—These are comparatively large oval- shaped parasites, just visible to the naked eye when viewed against a black background. The legs are long, and all are visible from the dorsal aspect. The suckers are carried on long trumpet-shaped_three-jointed pedicles, and are absent in the female on the third pair of legs and in the male on the fourth pair. The rostrum is long and conical. The posterior extremity of the male bears two triangular abdominal prolongations, each of which bears five bristles. These are the copula- tory suckers, and are absent in the female. 3. Symbiotes. — These, again, are oval in shape. The legs are long and thick, but the posterior pair is poorly developed and placed ventrally,so that,on viewing the parasite from the dorsal aspect, only three pairs are visible. The suckers are carried on short, broad, unsegmented pedicles. The rostrum is short and is broader than long. The male carries square abdominal prolongations, each bearing five bristles, and in the female these are rep- resented by two short cylindrical projections. The Symbiotes show a serrated edge, and the body is usually mapped out by broad lines, which extend from the proximal margins of the legs. 4. Demodecide.—These will be described when dis- cussing follicular mange in dogs (p. 21). Symptoms and Diagnosis of Mange.—The first sign of mange noticeable in any animal is a hyperemic condition of the skin, accompanied by the usual signs of skin irritation, such as scratching and rubbing the part. Gradually the hair is lost and the epidermis becomes thickened, and a collection of scales may appear cn its surface. The desquamated epithelium soon becomes caked together by exudate and blood into PARASITES AFFECTING THE SKIN II crusts. Pruritus becomes more intense, and, unless treated, the animal may lose condition through the continuous irritation and loss of rest. To diagnose with any degree of certainty a microscopical examination must be made, and the parasites discovered. The method of procedure is as follows : Find a recent lesion which has not been dressed with a parasiticide, remove all scabs, and scratch the surface exposed with a scalpel until bleeding is produced. It is advisable, some while before commencing, to have the animal stood in sunlight, as this increases the activity of the parasites, and brings them nearer the surface. The scales of epithelium, portions of hair and_ blood, thus procured are placed in a shallow watch-glass, covered with a little diluted liq. potasse, and allowed to stand for about five minutes, in order to dissolve the fat. The scrapings are then placed on a glass slide as thinly as possible, and covered with another of the same thickness. The two slides are then held between the finger and thumb of each hand, and each is gently moved about upon the other. This distributes the epithelial scales, and on examining with a 1-inch objective, there should be little difficulty in detecting the parasites, if present, in the scrapings. Time and a great deal of patience are necessary, and care must be taken to scrape deeply, more especially when examining for Sarcoptes. If the scabs are exposed to strong sunlight for an hour before examining, the mites will come to the surface, and are more easily demonstrated. In the case of Acari in the external ear, it is only necessary to treat the wax obtained as described. The presence of the Demodex folliculorum is not difficult to demonstrate, providing a fresh pustule is discovered. This should be pricked with a fine needle, and the contents squeezed out and placed on a glass slide. No alkaline treatment is necessary. 12 VETERINARY PARASITOLOGY Predisposing Causes, etc.—Mange arises from con- tagion, which may be either mediate or immediate. The condition of the animal and its environment have a great influence upon the chances of contagion, and upon the severity and duration of the disease. Army horses, under ordinary conditions, become affected with mange, with usually mere reddening of the skin. The symptoms rarely last more than a few days under these circumstances. Mange in Horses. Three forms of mange affect horses—viz., sarcoptic, psoroptic, and symbiotic. Of these, psoroptic is the most common, and symbiotic the least. Sarcoptic mange offers the greatest difficulty in treatment, as the mites burrow and are little affected by parasiticides smeared on the surface. : Sarcoptic Mange in Horses.—In horses the parasite is known as the Sarcoptes equi, and is extremely small. This form of mange principally attacks the trunk, more particularly the shoulders, neck, withers, and that portion of the body covered by the saddle. It then extends on to the quarters, and the patches may increase in size until the whole of the trunk is covered. It avoids the limbs and those parts covered with long hair, such as the mane and tail. It begins as small patches, which gradually increase in diameter. The areas are denuded of hair, become irregular in size and shape, and exhibit a greyish or pinkish surface, almost completely covered by a scab, usually thin and composed of dried blood and exudate. Occasionally the parts may bleed from rubbing. The skin becomes thickened and may crack, and, as a result of infection, pus may appear in the fissures. It is most commonly seen in horses in low condition and during emaciation resulting from various causes, but it may attack PARASITES AFFECTING THE SKIN 13 healthy, well-nourished animals; but in this case the natural defences are stronger, and so the disease is com- paratively easy to eradicate. Sarcoptic mange in horses produces symptoms of great skin itching, especially when the animal is exposed to sunlight and during the night. Ifthe parts are scratched with the fingers, the horse shows symptoms of apprecia- Fic, 2.—Sarcoptes Egu1: DorsaAL SURFACE. tion by smacking the lips together and nodding the head, and these signs were formerly considered diagnostic of the disease. Diagnosis is verified by the discovery of the parasite, but as this is merely a matter of chance, and may require many hours’ patient searching, it is but seldom that the practitioner exceeds a naked-eye diagnosis. 14 VETERINARY PARASITOLOGY Prognosis should be guarded, as the disease often resists treatment, and relapse is very common. It is extremely difficult to impress upon owners and stable- men the necessity of absolute disinfection of harness,rugs, and grooming utensils, and the prevention of reinfection. \ Fic, 3.—Psoroptes Equi (MALE): DorsaL SURFACE Psoroptic Mange in Horses.—The parasite responsible is the Psoropies communis, var. equi. This form of mange attacks sheltered positions, as the mane and tail, the intermaxillary space, the breast, sheath, and inner side of the arm and thigh. It does not extend below the knees and hocks, but may occasionally occur on PARASITES AFFECTING THE SKIN 15 the withers and back. It is transmitted from horse to horse. It produces intense pruritus, and the animal rubs the parts, and may produce serious sores. The Fic, 4.—SYMBIOTES Egut (MALE), VENTRAL SURFACE. parasite lives on the surface, and is more easily dis- covered. Symbiotic Mange in the Horse. —-The Symbiotes equi 16 VETERINARY PARASITOLOGY confines its attacks to the legs and feet, chiefly to the pasterns and fetlocks, and up as far as the knee and hock. Its progress is very slow. The skin becomes denuded of hair, then thickened. Fissures appear and discharge, and the exudate runs into the cracks and dries into scabs. The entire skin over the part takes on a wrinkled leathery appearance, and, owing to irritation, serious sores may be produced from rubbing. The symptoms of violent skin irritation are shown by stamping the feet, jerking up the limbs, often in a manner simulating “ shivering,” and rubbing the part with the opposite foot. It may be mistaken for grease or the condition known as mud-fever, but the intense pruritus characteristic of symbiotic mange and the presence of the mite are sufficient to verify the diagnosis. Treatment of Mange in the Horse.—In psoroptic, and more particularly in sarcoptic, mange the horse should be scrubbed all over with warm soda-water, followed by a weak solution of any creolin preparation. This should be rinsed off with clean water, and the horse scraped down and allowed to become thoroughly dry. One should next proceed to dress one half of the body, supposing that the disease is well advanced, with a suitable parasiticide, such as the sulphur, tar, and alkali dressing, of which the prescription was given when re- ferring to the treatment of ringworm in calves. This should be left on for four days, when the horse should be washed again and the other half of the body treated in a similar manner. To complete the process, the horse must be thoroughly washed again with hot soda- water, and all the grease removed. The dressing should be applied with a brush, such as an old dandy, and thoroughly rubbed in, not simply smeared on. Among other dressings which may be used is the so-called Vienna liniment : PARASITES AFFECTING THE SKIN 17 B OL. picis Sulphur nig. # 3 past Sapo. mollis 3 S.V.R. .. - 4a 2 parts M. Fiat lin. This dressing is not as satisfactory as the one previ- ously mentioned, but is less objectionable, as it is non- greasy and easily washed off. Lysol, creolin, creosote, and chinosol, are efficacious in suitable dilution, but need to be frequently applied. Symbiotic mange yields to similar treatment, but it is unnecessary to wash above the knees and hocks in most cases, and any of the dressings enumerated may be applied. Mange in Cattle. Sarcoptic mange in cattle is of very rare occurrence. Psoroptic and symbiotic mange are not uncommonly met with. Psoroptic Mange in Cattle.—This form of mange affects the root of the tail, and extends up the rump and on to the croup. Occasionally it affects the fore-part of the body, as the withers and neck. It usually occurs in cold weather, when the animals are housed, and rarely in cattle at pasture. It is somewhat difficult to diagnose, as it bears some resemblance to eczema and other skin diseases. It is contagious only from ox to ox. Symbiotic Mange in Cattle—Symbiotes bovis attacks cattle in the neighbourhood of the perineum, and espe- cially around the anus and the anal fossa. Eventually it extends to the inner surface of the thighs, and may even spread along the back. The lower portions of the limbs, as the fetlocks and pasterns, are fairly common seats of the disease. It seldom affects animals which are kept under hygienic conditions, and which are in good health. Treatment.—Any of the common dressings, as previ- 2 18 VETERINARY PARASITOLOGY ously described, may be used. The following is of great service in any animal in which the patches are localized and not of great extent : Kk Formalin (formaldehyde 40 per cent. sol.) .. MXXX. Glycerin is de a aco Bis . Aqua ad 3xij. M. Fiat lotio. Sig... To be applied once or twice daily. Mange in the Dog. The three varieties of mange which may occur in the dog are sarcoptic, symbiotic, and follicular mange. Sarcoptic Mange in the Dog.—This form of mange in dogs is due to the attacks of Sarcoptes squamiferus. It may affect any portion of the body, but usually appears on the head, especially the ears, the lower surface of the body, and along the back, near the root of the tail. The first sign is the appearance of red patches, usually small at first, which the dog constantly rubs. The skin on these patches is red and inflamed, and shows on careful examination small papules and sometimes vesicles, and the general appearance is not unlike that of eczema. The hair is shed, and the skin then becomes thickened and covered with a grey scurf, and in some cases shows wrinkling. The disease quickly spreads, and in a few weeks the whole body may be involved, and the dog becomes emaciated and anemic. Sarcoptic mange must be distinguished from follicular mange, from eczema, and from areas which have been bitten by fleas and scratched by the dog until they have become hairless and sore. Eczema starts more often along the middle line of the back, on the sides of the neck, and between the thighs. PARASITES AFFECTING THE SKIN 19 It shows more vesicles than mange, and usually there is more serous discharge. It is non-infectious. No para- site can be found, though it is a matter of difficulty to find the Sarcoptes under any circumstances, owing to the depth to which they burrow. Moreover, dry eczema, except when it has become chronic, yields more readily to treatment, and its appearance on the dog is usually much more rapid than in the case of mange. Mange in Cats. The Sarcoptes minor, which attacks the cat, is, as its name implies, very small. It is distinguished by the presence of numerous bristles along its dorsal aspect, and the anus is remarkable in that it opens on to this surface. The favourite situation is the head, and less commonly the limbs. The feet and paws often become affected also, from scratching the affected areas. The eyelids become denuded of hair in the majority of cases, and the skin over the whole area is much wrinkled. The cat frequently shakes the head, and constantly rubs against hard objects. Emaciation quickly sets in, and death may result. Treatment of Mange in the Dog and Cat.—It is abso- lutely essential to disinfect and destroy all bedding, rugs, etc., upon which the affected animal is accustomed to sleep ; otherwise a permanent cure is impossible. In treating terriers and the larger dogs, a soda-bath should first be given, and, when thoroughly dry, one half of the body should be dressed with the oily mixture previously described. In from four days to a week the dog should again be washed, and the other half dressed, and in the course of another week all grease should be removed by a soda-bath. Cure in most cases should then be complete. Unless the dog is kept out of doors, ol. picis and oily dressings are objectionable. The 20 VETERINARY PARASITOLOGY ol. picis may be replaced by ol. tereb., or by tinct. iodi, and soap may be substituted for oil—viz. : BR Sulph. nig... a os .. Bij. Liq. potasse .. 55 oh -. 58s. Ol. tereb. 28 ag ee .. 5vj. Sapo. mollis .. Ae es .. BUSS. S.ViR. 53 oi ais 26 .. Bij. Aqua Ae si e2 ad $viij. M. Fiat lin. Creosote, carbolic acid, and tar dressings must not be used on smail dogs, and only with caution on the larger breeds, and must be avoided altogether in the case of cats. Chinosol, lysol, and iodine are safer, but precautions must be taken against licking off the dressing. In cats sulphur ointment is most useful, but only a small portion of the body should be covered at one time with any greasy dressing. Symbiotic Mange in Dogs and Cats.—Svmbiotes auricu- larum confines itself to the inside of the ear. The para- site produces a great variety of symptoms, some of which arise from irritation and some as the result of nervous reflexes, while others may be ascribed to changes in the ear, such as abscess formation. The most characteristic symptoms are flapping of the affected ear or ears, shaking the head, and rubbing the ears against hard objects. Often the head is carried to one side. In other cases epileptic fits result from the irritation produced, and on several occasions cases have come to our notice in which the dog continually turned somer- saults along the ground, and this, in fact, seemed the only mode of locomotion. When deeply seated, the Symbiotes may be responsible for the formation of abscesses, which may account for the aggravated symp- toms just described. The abscesses develop in the middle or internal ear, with accompanying loss of PARASITES AFFECTING THE SKIN 21 equilibrium and inco-ordination of movement. The ear, on examination, may present a fairly normal ap- pearance, but more often shows a deposit of dark- coloured sticky wax. If this is thinly smeared over a glass slide and ex- amined microscopically, often quite a number of para- sites may be seen moving across the field. Treatment.—This consists in first cleaning out the ear with cotton-wool soaked in dilute spirit. The following dressings are suitable for application : BR. Creosote ut ond es eae TEx, Ol. caryoph. .. 23 ve .. xv. Ol. olivee as .. ad 3ij. M. Sig.: Pour a few drops into the ear r twice daily, and apply massage. Nocard advises the following : R Beta-naphthol eu i -. I part Ether meth. .. oe .. 3 parts. Ol. olive = fe 0 -. 10 parts Friedburzher and Fréhner recommend equal parts of Peruvian balsam and glycerin. Ear-cones, with a basis of cacao butter, and contain- ing zinc sulphate and ext. belladonne vir., are very useful. ‘ If nervous symptoms are marked, nerve sedatives, as pot. bromid., strontium bromid., or chloral hydrate, should be employed in addition. Follicular (Demodectic) Mange.—-This disease is com- mon in dogs and cats, especially in large towns, and has also been observed in cattle and pigs, but in these is comparatively rare. Demoder folliculorum, the causal parasite, is of common occurrence in the skin of man, but without producing symptoms. The parasite is a representative of the Demodecide, which, like the Sar- coptide, are a division of the Acarina. 22 VETERINARY PARASITOLOGY It is a very degenerate parasite, is oviparous, and goes through a life-cycle similar to that of the Sar- coptide. In shape and general appearance, especially when viewed under a low power, the parasite much resembles a maggot, though when closely observed the differences in structure are obvious. It is about ;4, inch in length. ca RC ELSe BY Ke. The head is rounded from side to side, si\2% SS 2a and is somewhat longer than wide. It carries two pairs of jaws, placed one above the other. The lower pair, or maxilla, act somewhat like a pair of miniature tongs, and grasp the substances which the upper pair or mandibles masticate. In addition, the head bears a pair of feelers, which are finely segmented, and there is also present a structure known as the oral valve. The eyes are two in number, and are situated laterally. The body consists of a thorax and abdomen. The thorax is the widest por- tion, and bears four pairs of short three- jointed legs. The abdomen is triangular, the base being formed at its junction Fic.5.—Acarus With the thorax. It shows a dark area Demovex Fot- about its centre, supposed to represent TICOrORUM. viscera. The whole length of the body eee a is transversely striated, and the edges ; are correspondingly notched. In the hexapod larva and nymph stages the parasite has only small tubercles, in three pairs, in the place of legs, and the body shows no transverse striation. The Demodex inhabits the sebaceous glands of the skin, and one gland may contain from only 4 few up to a hundred or more parasites. The number AS Sy “i \ AS LD 7} hi TL A PARASITES AFFECTING THE SKIN 23 present determines to some extent the symptoms pro- duced. Symptoms in the Dog.—-There are two types of fol- licular mange commonly seen in the dog : 1. Pustular type (see also Appendix I.). 2. Squamous type. Follicular mange usually begins at the head, in the neighbourhood of the eyes, and extends to the ears, sides of the face, and forehead. It then appears on the feet and legs, especially inside the elbows, and gradually extends over the whole body. The first symptom noticeable is the presence of patches denuded of hair. The skin is hot and usually of a peculiar purple tint. Its surface shows a varying number of small papules and pustules. As the patches increase in extent, the skin thickens and becomes puckered into folds. These are most apparent on the head, and are especially noticeable in bulldogs, in which the skin becomes one mass of wrinkles. The bare patches now take on a dark slaty-grey colour, and the skin emits a most unpleasant penetrating doggy odour. If the pustules are squeezed, a small core of pus escapes, and this, if examined microscopically, is found to contain a large number of parasites. There is very little pruritus, and the dog seldom scratches, but more often shakes the body (formication), very much as a dog does when leaving the water. The skin becomes dry and fre- quently cracks, leaving fissures, from which a small quantity of blood may ooze. It is not uncommon to find one side of the head much swollen in an advanced case from subcutaneous cedema. This is more often observed in bulldogs. In the squamous type of the disease there are few or no pustules. The eyelids are most commonly affected, especially in Poms and small dogs, but the whole body 24 VETERINARY PARASITOLOGY is frequently attacked, and becomes denuded of hair. It assumes the same dark slaty-grey colour as in the pustular type, and is hot to the touch. Itching is very slight. The surface of the skin is dry and covered with desquamated epithelial scales. The absence of pustules is probably due to the fact that the parasites in this type of case are few in number in each sebaceous gland, and the inflammation set up is not sufficiently intense to cause pouring out of exudate and escape of leucocytes, and so pustules are not produced. In both types of the disease the animals appear wretched, become very emaciated, and often die. In the cat the eruption is similar, but it is more frequently confined to the head. Symploms in Other Animals.—In cattle the skin covering the whole body may be affected. The erup- tion takes the form of pustules about the size of a pea, but it is stated that cattle spontaneously recover from the disease. In pigs the Demodex is much broader than the Demodex jolliculorum of dogs, and the pustules they give rise to show a great tendency to become confluent, and so large swellings are produced. They attack the head, snout, and lower surface of the body. Prognusis.—This must be considered unfavourable, especially if the disease has been existent for any length of time. It is usually the case that, when one portion of the skin is apparently cured, the disease breaks out again in some other part, and although months may be spent in treatment, little benefit may result. Treatment. Among the commonest agents employed are the following : Sulphur, tar, iodine, potassium sul- phurata, zinc chloride, Peruvian balsam, ung. can- tharides, sublimate ointment, creolin, etc. x. In early stages, when the patches are few in number and of small extent, it has been thought ad- PARASITES AFFECTING THE SKIN 25 visable by some observers to cover the affected por- tions of skin with an agent which will exclude air, and so destroy the parasites. Collodion containing an anti- septic, such as acid salicylic or iodoform, has been used, and it is claimed to have been very successful. A solution we have found particularly useful in these cases is the following : RB Iodi resublim. ae oh sa By. Pot. iodid. oa si Be 34 “O]e8S: Hydrarg. biniodid. .. - es 685. S.VL.R. .. ate ane sa og: Oe Aqua ad 3iij. M. Fiat lotio, | This is applied once daily with a brush until the part becomes sore, when it is applied on alternate days. A lotion containing 4 per cent. formalin in glycerin and water will often effect a cure when the area affected is small in extent. 2. When the disease is more advanced, a course of treatment with the oily dressing previously described will often effect a cure, providing that the two separate halves of the body are thoroughly dressed. Another method of treatment recommended quite recently is the internal administration of pot. iodid., combined with inunction of the skin with white precipi- tate ointment, with the idea of producing iodide of mercury in the skin as the pot. iodid. is excreted. We have seen little, if any, benefit accrue from this line of treatment. Hunting and Duguid’s dressing is frequently em- ployed—viz. : BR Creosote he ais a cs ai. Liq. potasse .. as 4a .. Bij. Ol. olive : -. ad Oui. M. Fiat lin. 26 VETERINARY PARASITOLOGY Mr. Gray recommends an ointment composed of salicylic acid, 1; gum styrax, 1; sulphur, 1 ; lard, 9. The styrax causes this composition to penetrate well into the skin, and it is decidedly useful. Whatever treatment be adopted, the skin should be first washed and well kneaded with soap and water, and as many pustules as possible squeezed out. The dressing, when possible, should be applied with a good deal of friction. The general condition must be attended to, and arsenic in some form should be given in combination with laxatives. Sarcoptic Mange in the Pig.—This variety of mange first attacks the head, especially in the neighbourhood of the orbit and ears. The inner surface of the thighs is a common seat, but the whole body may eventually become involved. The affected areas become covered with silvery-grey scales of a considerable thickness. ‘When removed, the skin appears very much thickened and inflamed, and often shows wart-like elevations, which are in reality hypertrophied papille. The Sarcoptes suis is one of the largest of the mange- mites, and the females may measure $ millimetre in length, and hence be visible to the naked eye. Treatment.—-Sulphur and tar dressings in oil are usually quite efficacious. Mange in Sheep. All three varieties of mange are found in the sheep, but of these the psoroptic type, which gives rise to “sheep scab,” is the most important. Sarcoptic Mange in Sheep.—The Savcoptes ovis con- fines itself to those portions of the body which are covered with hair, and seldom attacks parts which bear wool. PARASITES AFFECTING THE SKIN 27 Its favourite seat is the head, particularly the upper lip, sides of the cheek, and ridge of the nose. The ears are less commonly affected. The disease may extend down the breast in a bad case. The skin shows a large number of vesicles, which burst and discharge a fluid, which dries into yellowish crusts. Pruritus is intense, and the sheep constantly rub their heads against the ground, trees, posts, or their neighbours. The scabs are thus torn off, and the bare patches bleed, and crusts of congealed blood are left on the face. Conjunctivitis is not an uncommon sequel, and may be followed by purulent ophthalmia and blindness. The sheep lose condition and may cease feeding, while the wool is rendered useless. The disease is very contagious, and so isolation is a matter of great importance, and care must be taken in parts where the disease exists not to introduce affected animals into a clean flock. Treatment.—The scabs must be first softened with alkalis, such as liq. potasse, mixed with oils or fats. This dressing must then be washed off, and one of the following parasiticides applied: Infusion of tobacco, sulphur ointment, creolin solution, or diluted tincture of iodine. The simplest and most efficacious is the sulphur turpentine and oil dressing previously mentioned. In this country ‘‘ head mange”’ is not a scheduled disease. Psoroptic Mange in Sheep (Sheep Scab)—Etiology.— The cause is the presence of Psovoptes ovis in the fleece. The parasite is usually conveyed to the sheep by immediate contact with one previously affected ; but as sheep have been known to contract the disease in places where there have been no flocks kept for as long as one or even two years, it is probable that the parasite is able to live for some considerable time apart from the host. It is certain that the mites can retain their 28 VETERINARY PARASITOLOGY vitality on a cast-off scab for a period ranging from one to two months, providing that the scab is kept in a moist situation. The parasite is quite visible to the naked eve, es- pecially when viewed against a dark background, and if exposed to the rays of the sun. The length of the adult male parasite is about $ mill- metre, or #, inch, while the female is rather larger. Crows and other birds which perch on the backs of sheep have often been accused of spreading the disease, and there is no reason to believe that this theory is incorrect. Symptoms.—Psoroptic mange may attack sheep of any age, but the members of the flock which usually show the earliest and most serious symptoms are lambs and yearling lambs, with fine, supple skins. Some breeds of sheep seem particularly predisposed to scab, though lack of condition plays a far greater part. Unlike sarcoptic mange, it is the parts most thickly covered with wool that become attacked, such as the neck, withers, back, and sides. The first symptom noticeable is intense pruritus, and the animals constantly scratch and rub the affected areas. The fleece becomes matted, much stained from scratching, and in many places it is torn out in the attempts of the animal to allay the itching. These symptoms are especially evident if the flock is driven, when the sheep so affected constantly halt and rub the bare patches. If one of these is gently scratched with the finger, the animal evinces signs of great satisfaction by nodding the head, smacking the lips, and wriggling the hinder parts of the body. If the fleece is parted at this stage, the underlying skin will be seen to be intensely inflamed and covered with numerous yellowish-white papules. These go through PARASITES AFFECTING THE SKIN 29 the vesicular and the pustular stages, and finally burst, allowing the escape of a sticky yellow exudate with an acid reaction, which soon dries into a scab. This scab grows in area, as the parasites now leave the centre and proceed to the margin, where they once more attack the skin, producing a fresh crop of pustules, and eventu- ally a fresh scab, which becomes confluent with the original one. The large crust thus formed has the appearance of dirty parchment. It drags out the fleece by which it is attached, and becomes raised from the skin. It then begins to show fissures, and is finally lifted off by the crop of new wool which grows beneath it. The surface of the body thus shows several different appearances. We will suppose that in a typical case some portions, such as the rump and the under surface of the body, are covered with sound normal wool. On the neck a recently affected patch shows matted, tangled wool and pustules beneath it. On the back we may see a parch- ment-like scab lifted off from the body, and close beside it an area of dry, thickened leathery skin, covered with desquamated epithelium, and in parts showing traces of a new growth of wool. On the sides where the sheep has been able to bite and scratch we may see an ulcerated patch, showing signs of sloughing or local necrosis. Diagnosis—1. There should be no difficulty in dis- tinguishing psoroptic mange from sarcoptic. The latter attacks the head, while the former seeks only parts covered with wool. The parasite in psoroptic mange is not difficult to discover. A portion of scab should be taken from the periphery, softened in diluted liq. potasse, well teased out, and examined microscopically. 2. Rain-Rot.—This is really a sebaceous folliculitis, occurring in autumn, after excessive rain, and may affect many members of a flock at one time. It is non- 30 VETERINARY PARASITOLOGY parasitic, and there is little pruritus. The wool often falls out in patches, but the typical symptoms of scab are absent. 3. Phthiriasis—Trichodectes are found around the point of the shoulder, and could be only with difficulty confounded with Psoroptes. 4. Sheep are sometimes the subjects of an ecthyma, which is seen on the inside of the elbows and between the thighs, but this could scarcely be confused with scab. Treatment.—This must be divided into preventive and curative. Preventive treatment comprises the prevention of primary infection and of infection of the rest of the flock after the disease has appeared in certain members of it. As sheep scab is a scheduled disease, the Board of Agriculture lays down a series of regulations, with the object of preventing and stamping out the disease. The Sheep Scab Order of 1905 is the last issued, and its provisions, in brief, are as follows : All suspected cases must be reported to the police, who call upon a veterinary surgeon to verify the diagnosis. The premises on which the sheep are kept are disinfected and the sheep dipped. It is illegal to expose infected sheep in a market for sale, and no sheep are allowed to be removed from the scheduled area without a licence. In districts where the disease is prevalent dipping of all sheep is made compulsory, and every owner of sheep is compelled to send in a return of the number he possesses. Before an owner can remove sheep from the scheduled area, he must produce an order, showing that they have been dipped satisfactorily, within a period of twenty- eight days from the time at which he wishes to remove them. In districts where the disease is prevalent the farmer PARASITES AFFECTING THE SKIN 31 should carefully dip all new sheep purchased or brought from another farm before introducing them into a clean flock. Isolation is a matter of the gravest importance, and pastures in which the disease has broken out should be avoided if possible (see also Appendix II). Curative Treatment.—The first proceeding is to shear all affected sheep, whatever the season, for under cover of the fleece it is practically impossible to destroy the Psoroptes. The second is to supply the animals with large quantities of nutritious food, as an improvement in condition materially aids cure. Curative treatment is divided into two methods : 1. “ Salving’’ and “‘ bottling.”’ 2. Dipping. “Salving ”’ consists in parting the fleece, and follow- ing this by inunction of the skin with mercurial ointment. “ Bottling ’’ is similar, but the medicaments employed are usually in the form of liniments, such as creolin, carbolic acid, tar, etc., in oil. Dipping is by far the best treatment. This must be performed twice, the second dipping being carried out after the seventh and before the fourteenth day, this having been found to be the period after destruction of the adult mites in which the eggs that have escaped destruction by the first dipping will have hatched out. This proceeding should be carried out three or four days after shearing. Various dips, many of which are proprietary, are in use, but the following are the most efficient : I. BR Arsenic .. = et .. IIb. Zinc. sulph. Ze ae -. 5 1b. ‘Aloes aa he ts sie Ube Aqua ay 4 ae -. 100 lb,=124 gals, The aloes must be first dissolved in a sufficient quantity of boiling water, and added to the remainder. 32 VETERINARY PARASITOLOGY II. B Arsenic Pot. carb. =e Sulphur aa 2 1b. Soft soap Water .. ai oe .. 100 gals. Due precautions must be taken against poisoning by providing a draining-pen, and by placing dipped sheep in a yard free of herbage. Lambs must be kept apart from the ewes, or they may become poisoned by sucking. The arms of the men employed in dipping must be free from wounds. The following dips are recommended by the Board of Agriculture : ITI. B Sulphur ie fs od -» 25 ]1b. Quicklime si so He -. 12$ Ib. Triturate until free from lumps, and boil with 20 gallons of water until dark red in colour, adding water up to 20 gallons to allow for loss by steam. When cool, decant and make up to 100 gallons. Iv. BR Carbolic acid (97 per cent.) .. -» 3 quarts Soft soap 6 : ses -» § Ib. Water .. oe a ee .. ad 100 gals. Dissolve the soap in the carbolic acid and add the water. V. B Offal tobacco ie! et -» 35 1b. Water .. e +. 21 gals. Steep for four days; strain and press residue to obtain all the extract; mix together; add flowers of sulphur, 10 lb. ; stir, and add water to 100 gallons. Symbiotic Mange in Sheep.— The Symbiotes ovis is a small parasite. It affects the limbs, especially the pasterns, and slowly extends upwards, and may reach above the knee and hock. Occasionally the armpits and groin are affected, with subsequent swelling of the limbs. PARASITES AFFECTING THE SKIN 33 Treatment consists in passing the animals through a trough containing copper sulphate solution, and in- unction of parts above the knee and hock with creolin ointment. This form of mange is very amenable to treatment. NON-PSORIC ACARIASIS. The non-psoric Acari comprise the Ixodide, or ticks, and the Trombidiide, or running mites. The Ixodide are by far the larger and more important group. They are large insects, macroscopic, and live in coarse grass and undergrowth. Dirty farms, with rough herbage, moorland, and untrimmed hedges, provide their ideal habitat. Ticks have flat bodies, protected by horny shields on both their dorsal and ventral surfaces. They are blood-suckers, and pass the parasitic portion of their existence on the bodies, chiefly on the limbs, of animals, on which they gorge themselves with blood until spherical in shape. The rostrum is composed of two barbed harpoons above and below a dart. In the middle is a sucking mouth. The anus is near the mouth, and when oviposit- ing, the eggs form clusters round the anterior extremity of the parasite. The feet terminate in hooks, for cling- ing. The larve possess great vitality, and can live many weeks without food. The adult females are very prolific, and may produce three broods in one year. There are two divisions of the Ixodide—viz., Rhipi- cephalus and Ixodes. In Rhipicephalus, or, as it is sometimes called, Boophilus, the rostrum is broad and the body rounded ; the legs are all inserted within a short distance from the head, and the tick possesses a pair of eyes. In Ixodes the rostrum is long and fine and eyes are 3 34 VETERINARY PARASITOLOGY absent. The body may be oval or conical, and there is a marked space between the limbs, the hindmost pair of which often take origin even from the lower half of the body. Life-History.—Ticks pass through the usual four stages in the course of their existence—viz., egg, hexapod, larva, nymph or pupa, and finally the adult sexual stage. The eggs are laid on the rough pasture which the ticks inhabit, usually at the roots of the tufts of long coarse grass and bracken. As each of these hatches Fic. 6.—Hexapop Larva oF RHIPICEPHALUS ANNULATUS (Enlarged).* there emerges a white six -legged or hexapod larva, at first destitute of any hard covering. This larva proceeds to climb a convenient blade of grass, to which it attaches itself by its two posterior pairs of legs. When an animal passes, the larva fastens on to the leg with its anterior limbs, and crawls up out of reach of the bushes and foliage, which might otherwise brush it off. It then buries its rostrum in the skin, and sucks blood * After Stiles(?) compare ‘‘Moussu and Dollar’s Disease of Cattle, Sheep, Goats, and Swine,” p. 418. PARASITES AFFECTING THE SKIN 35 for about two days, when it loses its clinging power and drops off. Some of the ticks complete their life-cycle on one animal, and in these the piroplasm is transmitted through the egg. It now proceeds to moult, and becomes the nymph, with eight legs, but differing from the adult in being destitute of sexual organs. It again seeks the summit of a blade of grass, and becomes attached to another animal host, on which it remains for about four days. It again gorges, and becomes black with blood, when it falls off, to again moult, and finally Fic, 7.—IxoDES REDUVIUS.* Enlarged. develop into the sexually adult tick. The females are now fertilized by the males, gorge, fall off, and lay their eggs. When full of blood, the ticks are dark in colour and opaque, and easily removed from their host. In the grass the tick abstains from food, and often fasts for a considerable period. In the asexual stages the tick shows no desire for any particular animal, but in the adult stage each variety of tick attaches itself to an animal of one definite species. In those ticks which require more than one host it is in the nymph stage * See p. 432 ‘‘Moussu and Dollar.” 36 VETERINARY PARASITOLOGY that the parasite first becomes a carrier of the various piroplasms, which cause those diseases grouped under the heading of ‘“‘ piroplasmoses,” and it is as an adult that it transmits the piroplasms to another animal. Except in the role of a transmitter of disease, none of the ticks harm their host to any extent. At the most, and only then when in considerable numbers, they give rise to itching, and possibly anemia. We append alist of a few of the diseases due to piroplasms, together with the ticks which transmit each : British Redwater.. .. Ixodes reduvius | Probably Ixodes ricinus identical. Hemaphysalis punctata. (In the pig) Ixodes plumbus. Texas Fever .. Rhipicephalus annulatus or bovis. South African Redwater Rhipicephalus Australis, var. de- coloratus (blue tick). Rhodesian Redwatey .. Rhipicephalus appendiculatus (brown tick). “ Carceag’’ of Sheep .. MRhipicephalus bursa. Malignant Jaundice, ov Hemaphysalis Lechi. Canine Pivoplasmosis South African Heartwater (In sheep) Amblyomma Hebreum. It is difficult to eradicate ticks from a farm, but the following methods are adopted : 1. Ploughing all rough pasture, trimming hedge- bottoms, and dressing the land with salt or lime. 2. Removal of ticks from infested animals by hand and by dipping. 3. Pasturing animals of a different species on the land, in order that the piroplasms may gradually die out. The ticks, however, are not easily destroyed by this means. The other non-psoric Acari are of little importance. The autumn grass mite Leptus autumnalis) is the hexapod larva of the harvest mite (Tvombidium holo- PARASITES AFFECTING THE SKIN 37 sericeum). It occasionally attacks horses and dogs, producing a pustular eruption and a considerable amount of itching. The pustules are at first small, but may reach the diameter of a shilling, and are seen on the back, on the muzzle, and between the thighs. The con- dition is quite amenable to treatment with parasiticides. PHTHIRIASIS (LOUSINESS). The lice include all the Aptera, with the exception of the fleas. The Pediculine are divided into Pedicu- lide and Ricinide. The two chief types of louse are Haematopinus and Trichodectes, the former being a division of the Pediculide, and the latter of the Ricinide. The true lice (Hematopinus) have a projecting rostrum, with barbed hooks, and in addition a hollow extensile sucker. The legs are provided with hooked terminal joints. They have simple eyes, are wingless, and pass through none of the ordinary intermediate stages between the egg and the perfect parasite, as in the Acari. The eggs are oval in shape, are attached to the hairs, and are commonly known as “nits.” In Hematopinus the shape of the body is generally said to resemble that of a Dutch doll—that is to say, the thorax is larger than the head, and the abdomen larger than the thorax. With the exception of the sheep, all animals may be affected with one or more varieties of Hematopinus. The Hzmatopinus forms are blood-suckers. Trichodectes.—These are epidermis-eaters, and the head is modified for this purpose. Instead of being terminal, as in Hematopinus, the mouth is situated on the under surface of the head, which is broad and shield-shaped. In these the thorax is the smallest segment of the body. 38 VETERINARY PARASITOLOGY The various lice found on each animal are enumerated below : Trichodectes pilosus. Hematopinus macrocephalus. Horse Trichodectes pubescens. Hematopinus eurysternus. Ox { Haematopinus vituli. Hematopinus tenuirostris. Trichodectes scalaris. Sheep { Hematopinus pedalis. i Trichodectes spherocephalus. Pig .. Hematopinus urius. f{ Hematopinus piliferus. Dog *\ Trichodectes latus. Cat .. Trichodectes subrostratus. Symptoms.—These vary a good deal, in accordance with the variety of louse present. The Hematopinus Hi roy } Ly i Mh prea eee : = ru Fic, 8.—TRICHODECTES SCALARIS. Greatly enlarged. Au seen forms suck blood, and hence cause more irritation than those which live on desqua- mated epidermis and secretions. The usual signs are emacia- tion, irritation, and rubbing, scurfiness of the skin, with the hair erected, and sometimes crusts or blood from rubbing. Usually the lice them- selves or their “‘ nits ”’ can be found. They are more active in summer than in winter, and may remain on one animal a very long time. PARASITES AFFECTING THE SKIN 39 In the Horse.—They may be found under the mane, at the root of the tail, and on the shoulders and quarters in advanced cases, and seldom or never under the belly. In Cattle—Trichodectes scalaris is much the com- monest. It has no predilection seat, and may be found all over the body. Hematopinus forms are located along the neck and spine. In sheep, Trichodectes are commonest round the point of the shoulder, and leave bare patches. In Pigs.—H emato- pinus urius is the largest of all lice. It attacks the neck, head, and armpits, and frequently causes death in young pigs. Treatment. — Care must be taken to prevent the spread- ing of the parasites to other animals by grooming utensils or Fic. 9.—Hamatopinus Macro- any other means. oe es To destroy lice, s oe creolin baths are best, repeated in a week. Jeyes’ fluid (zr in 60) is very efficacious, especially if some soft soap is previously dissolved in the water. Other agents which may be employed are : Decoction of stavesacre (rin 20) ; mercurial ointment rubbed down 40 VETERINARY PARASITOLOGY the back in cattle ; and various so-called insect powders, such as pyrethrum, stavesacre seeds, etc. Decoction of tobacco (1 in 20) is often used. Sheep may be dipped. The same precautions as regards disinfection should be taken as in mange. A mite which sometimes causes symptoms allied to those of Phthiriasis is the Dermanyssus gallina, or fowl mite. This often attacks horses kept in a stable in which fowls are in the habit of roosting. Dermanyssus avium may cause similar symptoms, and their presence is said to result from swallows or sparrows nesting in the roof of the stable. The mites attack chiefly the neck, withers, and back, causing loss of hair and a scurfy appearance of the skin, accompanied by intense pruritus and constant rubbing. The mites can usually be found:on the skin. Treatment is similar to that for phthiriasis. Pulicide (Fleas). On dogs Pulex serraticeps is common. It is large, and brown in colour, while Pulex ivritans of man is smaller and darker. The complex life-cycle may take place on one host. This is often observed in the cat, especially in long- haired varieties, on the skin of which often a consider- able number of comparatively large white eggs may be found. Symptoms.—There is constant irritation and scratch- ing, and occasionally an eruption may be seen on the back. Fox-terriers seem particularly liable to this eruption, and in these it takes the form of dark-coloured circumscribed hairy patches, with irregular surfaces. They are frequently confounded with mange, ringworm, and other skin affections. Treatment.—Creolin baths are most useful. In the PARASITES AFFECTING THE SKIN 41 smaller varieties of dogs and in cats ol. anisi or ol. eucalypti in spirit are best, though these do not neces- sarily destroy the parasites. All mats and bedding should be destroyed, and kennels disinfected and limewashed. Cutaneous Filariasis. In Russia, Hungary, and some few other countries, horses, more particularly thoroughbreds, often exhibit symptoms of what is known as “ parasitic skin-bleed- ing.” The cause is a worm, either Fularia multipapillosa or Filaria hemorrhagica. ° Filaria multipapillosa is from 2} to 23 inches in length. Its cephalic end shows a series of papille, arranged in rows, from which it derives its name. The body is transversely striated. Within the nodules the worm is coiled into a spiral. It is ovo-viviparous, and is prob- ably carried to various parts of the body at some stage by the blood-stream. Symptoms.—These are more apparent in warm weather, and may recur during several successive summers. Non-inflammatory nodules about the size of a pea occur on the neck, shoulders, and breast. From these there exude drops of blood at intervals. The hair becomes matted, and after a while streaks of blood are seen on the skin. The general health is unimpaired. They often cause inconvenience owing to their position under the harness. Treatment.—Clip the part, and apply alcohol or tinct. iodi. Any parasiticide may be employed. Arsenic should be administered internally. In Hungary the swelling is incised, and the worm extracted just at the time when it is about to open. 42 VETERINARY PARASITOLOGY Filaria Irritans. This parasite in the larval state causes a disease of the skin known as “ parasitic granular dermatitis,” or “summer sores.” The parasite is found in South Europe, Algeria, and India. It becomes surrounded by a calcareous capsule, and remains in the skin all the summer. Probably it gains entrance from the surface. The nodules are commonest on the parts normally covered with harness, and probably friction plays a part in introducing the parasite. Treatment.—Sulphide of arsenic has been successfully used. Phenol or iodoform collodium are of service. Dracontiasis. In India, Africa, Egypt, Persia, and South America, the guinea-worm (Fularia Medinensis) sometimes lives in the skin of the horse, dog, or cow. It is a large worm, and buries itself in the connective tissue. In time one end emerges through an orifice in the skin, and the Indians then remove it. It is stated that if the worm is broken in the process, death of the patient at once follows, but this is open to grave doubt. Embryos are set free by the rupture of the body of the worm, and pass this stage of their existence inside small crustaceans. After some while they are taken into the body of one of the larger animals during the act of drinking, and reach the stomach, where fertiliza- tion takes place. The males then die, and the females bore to the surface. Fleming has recorded chronic lameness in horses caused by this parasite. PARASITES AFFECTING THE SKIN 43 DIPTERA AFFECTING THE SKIN. Besides the Aphaniptera, or fleas, already described, members of the Nemocera and Brachycera may attack animals in the réle of transitory parasites. The Nemocera possess long, extremely fine antenne, made up of six distinct segments, and are thus distin- guished from the flies. The larve have distinct heads. They include the Culicide, or mosquitoes, and the Simuliide, or sand-flies. The Brachycera are divided into the Tabanidz (breeze- flies) and Hippoboscide, or Pupipara. I. Culicide (the Mosquitoes). These are of more importance in human than in veterinary medicine, as they are the carriers of the organism which causes malarial fever of man. The females are the more important, as the males are not blood-suckers, but live on the juices derived by suction from flowers and plants. Several generations are pro- duced in one season. The females are fertilized by the males late in autumn, and then proceed to hibernate. In the early spring they search for a marshy spot, and lay their first batch of eggs in close vicinity to water. The larve are aquatic, and in about a fortnight they become pupe. A few days later the perfect insect emerges. The gnats are a well-known species, extremely com- mon in the neighbourhood of trees and bushes, among the foliage of which they rest after feeding. The buzzing sound caused by the rapid movement of their wings is only too well known. 2. Simuliide (the Sand-Flies). These are often spoken of as buffalo-gnats. They are small and thick-set, and have not the characteristic 44 VETERINARY PARASITOLOGY buzz of the mosquito when flying. They are gregarious, and move in flocks, settling occasionally, but never appearing to rest for any length of time. The larve are aquatic. Only the females are blood-suckers. They attack only unprotected portions of the body, as the mucous membranes, especially the conjunctiva and the skin over the inside of the thighs and ears. They punc- ture the skin, producing raised swellings and intense irritation, followed by desquamation of the epidermis. Occasionally, when a large number attack the skin, serious symptoms may result. The chief are dyspneea, associated with fever, which may be followed by death. The Brachycera are flies with short antenne. Usually they are winged, and have the posterior pair rudimentary. Larve apodal, with no distinct head. The chief families are : Tabanidz (breeze-flies). Muscidz (house-flies). (Estridz (bot-flies). Hippoboscide, or Pupipara. FODH I. Tabanide (Breeze-Flies). These have a broad, flattened body, and the head broad and flattened from before to behind. The pro- boscis is capable of piercing the thickest hide. These flies are distributed all over the world, and are to be seen in the heat of the day, usually in the neighbour- hood of woods, where, by the buzzing sound they make during flight, they strike terror into cattle and horses in the neighbourhood. The breeze-flies are responsible for the spread of surra, and it is not unlikely that they might convey the bacilli of anthrax. PARASITES AFFECTING THE SKIN 45 There are hundreds of species, of which may be men- tioned : The Autumnal Breeze-Fly.—18 to 20 millimetres long. Thorax grey, with four brown longitudinal bands ; abdomen with three rows of white spots ; legs yellowish- white. The Ox Breeze-Fly.—A very large fly, 27 millimetres long. Thorax covered with yellow hairs, with black longitudinal bands ; abdomen brownish, striped with fawn. Each ring bears on the middle of its dorsal surface a white spot. Allied are the Hematopota, of which may be men- tioned the small rain breeze-fly (H@matopota pluvialis). 2. Muscide (House-Flies.) These have a large number of genera and species. Two groups are parasitic during the larval stage: (x) Sarcophaga ; (2) Lucilia. The following are parasitic (blood-suckers) during adult life : I) Stomoxys. 2) Glossina (tsé-tsé). ) Hematobia. (4) Muscide. (5) Cstride. (6) Hippoboscide. Stomoxys Calcitrans much resembles an ordinary house- fly, but its head bears an elongated proboscis, extending far in front. It attaches itself usually to the legs or neck of a horse, and can only with difficulty be knocked off. It causes great irritation, and in fine-skinned horses the attack gives rise to a papule. Glossina Morsitans (Tsé-tsé Fly)—Similar in appear- ance to a house-fly. Proboscis very long and slender ; 46 VETERINARY PARASITOLOGY thorax chestnut, with four black longitudinal stripes ; abdomen yellowish-white, composed of five segments (the last four each carry a large black spot) ; wings more opaque and more leaden in colour than those of the house-fly. It is this fly that conveys the dreaded nagana of Africa. 3. The stride. These are exclusively parasitic. They have large wings, and the body is usually covered with downy hair. The abdomen is composed of six rings, and terminates in an extensile ovipositor. By means of this the female deposits eggs on some portion of the body. The larval stage is parasitic. Hypoderma Bovis.—Length, 13 to 15 millimetres. Head grey ; thorax grey on anterior half, black on pos- terior half, and bears wide longitudinal black bands ; abdomen black, shows three bands of coloured downy hair, anterior yellow, middle black, posterior orange ; wings brownish. The fly is active from the beginning of July to the beginning of September. It lays its eggs along the back, shoulders, and occasionally on the fore-limbs. The flight of this insect is accompanied by a loud buzzing noise, which terrifies cattle, although no pain is caused by the fly, as the ovipositor is soft, and does not penetrate the skin. The female deposits only one egg at a time, and then leaves the host, makes a short flight, and returns to repeat the process ten or twelve times. The eggs are white and elongated, and carry a brown terminal appendage, which fastens them to the hairs. The larvee are known as “ warbles,” and live in the subcutaneous tissue. Probably the eggs or young larvee are licked off, and after passing into the alimentary tract, finally reach this position. Nothing is noticeable during the winter, but in the following spring small non- PARASITES AFFECTING THE SKIN 47 painful elevations about the size of a hazel-nut appear on the skin of the back and arms. In each of these is a ‘“‘warble.”’ At the summit of each elevation is a small hole, and the larva applies its posterior extremity with its “ breathing-holes”’ to this. In June the larva emerges through this apical orifice, after it has become enlarged. The ‘“‘ warble’? now becomes buried under leaves or straw, and after passing through the chrysalis stage, finally develops into a fly. The larva is brownish in colour, and composed of eleven rings. In shape it is conical, and much resembles a “bot.” The head bears two hooks for anchoring, arranged at right angles. The spines are arranged in three rows on each side, leaving out the centre portion, except in the last two segments, which are unarmed. The lateral prominences consist of an upper and lower in each segment, and are well marked. When mature, the larva measures 22 millimetres to 28 millimetres in length, and about 15 millimetres in breadth at the widest part. Treatment is usually unnecessary. If desired, the elevations may be coated with salicylic acid, or iodoform collodion, or even Stockholm tar. These suffocate the parasite by closing the air-holes. When the larva is ripe, it may often be squeezed out, especially if the skin over the elevation is first slightly nicked with a bistoury. Prevention is of more importance. The backs of cattle should be dressed during the months the fly is active with a mixture of sulphur, ol. picis, train-oil, and rape-oil, at least once weekly, to ward off the attacks of flies. Hypoderma Equi (Loiset).—This parasite is found in Holland, Belgium, and France. It produces cutaneous tumours containing a larva, and in all its characteristics much resembles Hypoderma bovis. 48 VETERINARY PARASITOLOGY The larva is only 9 to 10 millimetres in length. It has no spines and no oval hooks, and the skin is very thin and transparent. The tumours usually arise under parts which are commonly covered by harness, _, such as the neck, withers, and 7 back. Curative treatment may be applied, as in the ox. Gstrus Ovis is a small greyish-coloured fly, 10 to 12 millimetres in length. Thorax brownish-grey, streaked with dark obscure lines; abdomen slightly hairy, marbled with yellow, black, and white. The wings carry at their bases three black spots. The fly is active from May to October. The larve enter the nasal cavities of sheep, and finally reach the sinuses and horn-cores. They will be discussed more fully later. Fic. 1o.—Cistrus Equi. 4. Hippoboscide, or Pupipara. The female deposits the nymph. There are two species of importance : I. Hippobosca Equina (the Spider-Fly).—This fly attacks the soft parts of the skin of the horse, or even ox or dog, especially around the anus, eyes, and groin. It does not puncture the skin, but merely irritates. It is only 8 millimetres in length. It is a very obstinate insect, and can only with difficulty be driven away. It causes great stamp- ing and kicking among animals with fine sensitive skins. Hippobosca rubipes is a native of South Africa, and is PARASITES AFFECTING THE SKIN 49 believed to transmit the Trypanosoma Theileri, which causes the so-called biliary fever of cattle. (2) Melophagus Ovinus (Sheep-Ked).—This insect is without wings, and much resembles a louse. It lives in the wool of sheep, and finds its nourishment in the grease, scurf, and droplets of exuded blood. It is greyish-brown in colour, with a small narrow thorax and a large oval abdomen. Length, 3 to 5 milli- “metres. Muscide.—Some of the Muscide exist on the skin while in the larval state. Sarcophaga Magnifica is a greyish fly, 10 to 30 milli- metres in length.. It is viviparous, and deposits its larve on wounds or moist surfaces. Cattle are most commonly attacked. In the British Isles Lucilia Cesar and Lucilia sericata are the commonest. Lucilia macellaria is common in America. Lucilia sericata is of a greenish-blue colour, and smaller than Lucilia Cesar, which has a golden sheen. The former has the first ring of the abdomen black, and the latter the first two rings. These flies deposit their eggs on the fleece of sheep, particularly round the anus or where there is a wounded surface. The eggs hatch the same day. Cupri sulph. is the best agent in use for the purpose of destroying the larve. CHAPTER II PARASITES OF THE ALIMENTARY TRACT VERMES THE Vermes are non-vertebrate animals, possessing soft contractile bodies, devoid of an endo-skeleton, but con- stituted of a number of segments. They possess no articulated limbs. The organs comprising the secretory system are arranged in pairs. With the exception of the leeches, all the members of the Vermes under this heading which we are about to discuss are classed as Entozoa, or intestinal worms. Their natural habitat is to be found in some portion of the alimentary tract of a larger animal, apart from which but few can maintain their existence. They have no respiratory system, and hence need no circulatory system. The Vermes are divided into two chief groups : 1. Annelida. 2. Helminthes. 1. ANNELIDA. The only members of the Annelida which are parasitic are the leeches, of which Hemopfis sanguisuga, the horse- leech, serves as an example. The Annelides are the only invertebrates which have red blood circulating in a double system of bloodvessels. The body is soft, fiat or cylindrical, and shows distinct transverse rings. Hemopis sanguisuga is a member of the Hirudine. 50 PARASITES OF THE ALIMENTARY TRACT 51 It has an elongated body, flat on the ventral surface: and rounded on the dorsal surface. The mouth carries a tri-radiate, three-lipped sucker, used both for the purposes of assimilation and locomotion, and there is an anal sucker in the form of a flattened disc. The oval sucker is soft, and so the horse-leech is unable to attach itself, except to an abraded surface or a mucous membrane. The Hirudo medicinalis, on the other hand, has hard jaws, and is able to puncture sound skin. Although the leeches are hermaphrodite, a pair are necessary for fer- tilization, the penis being situated at the anterior end of the body, and the vulva a short distance behind it. The horse-leech frequents muddy pools, and the young parasites enter the pharynx of horses, asses, mules, or even man. During the process of drinking they become attached to the mucous membranes, from which they suck blood. Symptoms.—When the leeches are present in great numbers anemia and debility arise from loss of blood. The patient frequently coughs, and such attempts to remove the parasites are followed by discharge of blood, which has accumulated in the pharynx, down the nose. This is particularly seen when the animal is at work. Sometimes hundreds of leeches may be present at one time, and cause dyspnoea through obstruction of the pharynx. Treatment.—Prophylactic treatment consists in pre- venting the animals from drinking water from streams or pools infested with leeches. When this is im- possible, the water should be filtered through finely perforated metal trays, or net muzzles may be used while drinking. Curative treatment is usually successful. Strong salt solution on a sponge should be applied to the pharynx, as this dislodges the parasites. 52 VETERINARY PARASITOLOGY 2. HELMINTHES. These are divided into : 1. Platyhelminthes, or Platodes (flat-worms). 2. Nemathelminthes, or Nematodes (round-worms). The former are practically all hermaphrodite. They are again divided into two classes : (x) Cestodes. (2) Trematodes. (1) The Cestodes contain the tapeworms. They have long, flattened, ribbon-like bodies, distinctly segmented, and a head provided in most cases with hooks and suckers. The Tenioide are the most highly developed. The Bothriocephalide are allied. In the Tznioide in general the head bears from two to four suckers. Between these, and centrally placed, there may be a rostellum, armed with one or more circles of hooks or spines, or in some cases there is merely a depression provided with a pore. The body tapers anteriorly, and the segments gradu- ally become ripe from behind forwards; hence the ter- minal segments are usually crammed with eggs. The segments multiply by a process of division from behind the head at the same rate as the terminal segments are shed or have withered, as the case may be. Each seg- ment is hermaphrodite, and provided with one or two genital pores opening out from a uterus, usually con- sisting of a median trunk and numerous lateral branches. The position of the genital pores varies. Thus, in Tenia cucumerina there is one on either side of each segment, while in Tenia marginata they are arranged on opposite sides, one in each segment. In Tema litterata, again, the genital pores are centrally placed. In all the Tenioide the embryo escapes from the ovum and enters the alimentary tract armed with six PARASITES OF THE ALIMENTARY TRACT 53 hooks, and is known as the “‘ proscolex.” It leaves the intestine, penetrates into the tissues of the host, loses its hooks, and becomes a vesicle, from the inner surface of which develops the head of the future tapeworm. This head has received the name “ scolex.’’ When the carcass or portion of the carcass of an animal thus infested is eaten by another animal, the scolex is liberated, attaches itself to the mucous mem- brane of the intestine, and develops a number of seg- ments, or proglottides. The terminal segments pass out, and are ingested by yet another animal, and so the cycle commences afresh. (2) The Trematodes have a flattened, oval, or lanceo- late body, which is non-segmented. Those which are parasitic belong to the Distomata—that is to say, they have an anterior oval sucker and a round or oval ventral sucker, varying in position in the different members. They are hermaphrodite, but individual coitus is essential. The genus Bilharzia (Bilharzia crassa) inhabit the blood. They are not hermaphrodite, and the male and female are always attached, the male lying in a groove running the length of the female. The Distomata comprise : (a) Distomum. (0) Amphistomum. (c) Gastrodiscus. (d) Bilharzia. The flukes are of great importance, as they inhabit the bile-ducts, and cause the disease known as “ liver-rot.”’ Nemathelminthes. These are round-worms, as opposed to the Platyhel- minthes, or flat-worms. The sexes are nearly always distinct. 54 VETERINARY PARASITOLOGY They are divided into two chief orders : 1. Nematoidea (the Nematode worms). 2. Acanthocephala (the thorn-headed worms). 1. THE NEMATODES have a transversely striated skin. They possess a digestive canal running the whole length of the body, but no circulatory apparatus. They may be found in any tissue of the body, except the osseous skeleton. Their colour may be white, red, or brownish. The head may be armed, but definite hooks, such as are seen in the Tzeniz, are absent. In many the anterior end of the body carries just behind the head a pair of small membranous wings. Often there is a caudal pouch into which the genital duct and intestinal canal open by means ofacloaca. In the males chitinous spicules are often present, and are used in the process of copulation as “‘ claspers.’’ The Nematodes are oviparous or viviparous, and the females have a vulva on the floor of the body. Into this the uterus opens. This organ is provided with one or two ovarian tubes. In the majority the life-history has not been thoroughly worked out, but it is evident that some members complete their life-cycle in one host, while others require an inter- mediate host. The females are by far the commoner, and are larger. The males often exhibit spiral coiling of the posterior extremity. The Nematoidea are divided into : (x) Ascaridze. (2) Oxyuride. (3) Filariide. (4) Trichotrachelide. (5) Strongylide. (1) Ascaride.—The body tapers towards each ex- tremity. The mouth has three lips, and between these PARASITES OF THE ALIMENTARY TRACT 55 is a short tube, which can be slightly protruded. The male has no caudal pouch, but has two spicules, or “claspers.” The females have a straight digestive canal, and two tubular, spirally-arranged ovaries, several times longer than the body. They open at the vulva, which is situated at about one-fourth of the length from the anterior extremity. The Ascarides inhabit the small intestine, and may enter the stomach. The lumbricoid worms are found in the large intestine. (2) Oxyuride.—These worms inhabit the large intes- tine. They are oviparous. The mouth is provided with three lips, and the tail is tapered and much finer than the remainder of the body. The caudal pouch is absent in the male. (3) Filariidee.—The body is long, slender, and thread- like, and the rings are less pronounced. The mouth is a circular opening. In females, the vulva is situated at the anterior end of the body. The males usually have the tail rolled up. They are not found in open cavities, but inhabit the parenchymatous tissues, being frequently embedded in the subcutaneous tissues (see Cutaneous Filariasis, p. 34), tendons, or within the an- terior chamber of the eye. These represent the Filaria type; but the Spiroptera embed themselves chiefly between the layers of the viscera, such as the cesophagus and stomach, in the form of nodules, under the mucous membrane. (4) Trichotrachelidze.—These are so called on account of the beaded or constricted cesophagus. The body is extremely slender, and tapers at the anterior extremity. There are two genera : (a) Tricocephalus, usually inhabiting the intestine. (0) Trichina, usually found encysted in muscular tissue. 56 VETERINARY PARASITOLOGY (5) Strongylide.—lIn these the body is rounded, and but seldom thread-like. The mouth bears six oval papille. The males have the vent enclosed in a divided or entire caudal pouch, from which the organ of genera- tion can be protruded. There are usually one or two “ claspers.”’ The three chief groups of the Strongyles are : (a2) The Eustrongylines. (0) The Strongylines. (c) The Sclerostomines. The chief differences are set out in the following table : Mouth. Caudal Pouch. Eustrongylines .. Non-chitinous Not ribbed Strongylines ee Non-chitinous Ribbed Sclerostomines .. Chitinous Ribbed 2. THE ACANTHOCEPHALA. These worms are provided with a sort of proboscis, set with recurved spines, by means of which they attach themselves to the intestinal mucous membrane. Echinorhyncus gigas of the pig is the largest known member. Digestive organs are absent, with the exception of two small blind tubes arising at the base of the pro- boscis. The males probably fertilize the ova after they have been excluded. PARASITES OF THE ALIMENTARY TRACT 57 PARASITES INHABITING THE ALIMENTARY CANAL OF THE HORSE. Csophagus and Stomach. Strongylus Axei.—This is a small filiform worm, usually about 6 or 7 millimetres in length. It coils itself up under the mucous membrane in the form of a small nodule. It causes no symptoms, and is of little clinical importance. Filariide.—Two Spiroptera may inhabit the stomach of the horse. These are Spivoptera megastoma and Spiroptera microstoma—i.e., the large-mouthed and small-mouthed Spiroptera. Their average length is I centimetre (2 inch). They may be found free in the cavity of the stomach, but more frequently embedded in raised nodules in the mucous membrane, chiefly in the cardiac portion, and ranging in size from a pea to a walnut, with a small aperture at the summit. As the nodules grow older they become sur- rounded by connective tissue, and finally by a calcareous capsule. They appear to be more common in the ass than in the horse. Aa -aon te Fic, 11.—Larva They may produce chronic indiges- oF Gastro. tion, or even gastritis, with ulceration PHILUS Equi. : The horse and slight hemorrhage. cibest® Gastrophilus Equi Larve.—The com- mon horse “‘ bot’’ is the larva of the fly known as the Gastrophilus, or Estrus equi. The latter is a compara- tively large fly, with the proboscis directed forwards. The colour is a mixture of orange, yellow, and brown. The wings each show a light brown bar and two ter- minal spots of the same colour. It is a common parasite in the stomach of the horse, especially in those 58 VETERINARY PARASITOLOGY horses which have been at grass during the months in which the fly is active. The eggs are laid by the adult female, and glued to the hairs of the fore-limbs of the horse, or in some position from which they may be easily reached by the mouth. The eggs are provided with “‘ opercula,”’ or lids, which open and liberate small maggot-like larve. These cause irritation, and are licked off by the horse, and on reaching the stomach attach themselves by means of their hooked mandibles to the mucous mem- brane of the cardiac end of the stomach. They then undergo two moultings, and finally develop into the so-called ‘‘ bots.” Each bot is pyriform in shape, tapering towards the head, and is composed of eleven segments, the first eight of which carry a double row of stiff spines directed back- wards. The anterior tapered end carries two smooth antennz, while the posterior end has two pores or aper- tures for breathing. This bot is a dirty white in colour. Bots may migrate, and so reach the brain, larynx, pharynx, or bladder. The larve remain in the horse’s body for about nine months, and pass out with the feeces in the spring. After excretion, they shrivel and take on the chrysalis stage. They then undergo three moults, and finally emerge as adult perfect insects. Another variety of bot which is fairly common in this country is the Gastvophilus hemorrhoidalis. In this case the fly lays a number of brownish eggs around the muzzle and lips of the horse. These bots are of a dirty green colour, and may be frequently seen after the horse has passed feces, attached to the inner rim of the anus. Its habitat is identical with that of Gastrophilus equt, but it remains in the rectum for a little while instead of passing out at once. In Russia Gastvophilus pecorum is the common bot, and is occasionally seen in Russian ponies brought over PARASITES OF THE ALIMENTARY TRACT 59 into England. It is of a dark red blood tint. The colour is densest at the head, while at the tail end it is much lighter. In Australia Gastrophilus nasalis is common, and it is occasionally seen in England. The bot attaches itself to the pyloric end of the stomach and to the duodenum. It is frequently found in the pharynx and cesophagus, causing dyspnoea and coughing. Symptoms.—As a general rule, bots cause little or no disturbance. Occasionally chronic indigestion may result, and this may be associated with ulceration or perforation of the stomach wall. Colic occasionally results from their presence, and spasm of the cesophagus, associated with retro-peristalsis, has been noticed when bots have been present in sufficient number to cause obstruction. Treatment.—Owing to their great vitality, it is prac- tically impossible to introduce medicinal agents into the stomach in sufficient concentration to destroy the bots. In the spring they leave the horse, and should then be destroyed, in order to prevent increase in the number of bot-flies in the succeeding year. The following prescriptions are in common use: BR Creolin a ss a .. Bij. Ol. tereb. oe 24 oe .. §j-ss. OL lini .. ass i 2 .. ad OQj. M. Fiat haust. R Carbon disulphide .. : ss. This is best given in a epeile: BR Benzene 23 a a sa Be Tinct. iodi. .. 8 at .. 38s. OL. lini .. Se is ae .. adO,j. M. Fiat haust. B Creosote des es os aa Bh. Chloroformi .. Ze oe ve aij - Ol.{tereb. is a ae +. By.ss. Ol. lini .. Ne a aa vs Os M. Fiat' haust. 60 VETERINARY PARASITOLOGY Gastrophilus hemorrhoidalis may be removed from the rectum by injections of salt solution. Bots, when present in the pharynx, may be removed by the use of the above mixture applied on a long brush or on a sponge fastened on a stick. Among the parasites sometimes found in the stomach of the horse, Ascaris megalocephala must be included, but will be discussed later. Ganglyonema scutatum may sometimes be found in the cesophagus. Intestinal Parasites of the Horse. TANIA. The Tenia which inhabit the intestine of the horse are only three in number, and all belong to the Anoplo- cephalinz (the unarmed tapeworms). The three Teenia are : 1. Tena perfoliata. 2. Tema plicata. 3. Tenia mamillana. Of these, Tenia perfoliata is by far the commonest. It inhabits the large intestine, particularly the czecum. Tenia mamillana is very rare, and has seldom, if ever, been seen in horses in the British Isles. It inhabits the small intestine, as does also Tenia plicata, which is by no means uncommon. Tenia Perfoliataa—This worm ranges from 25 to 4o millimetres in length (1 to 1? inches), and is about ro millimetres (? inch) wide. The head is four-sided, large, and rounded, while the four suckers are rounded and placed at the extreme end of the head. Tenia perfoliata may easily be recognized by the presence of two flaps on each side, which project back- wards, and are quite easily visible to the naked eye. PARASITES OF THE ALIMENTARY TRACT 61 Tenia Plicata is by far the largest of the three. In length it ranges from 1} to 8 centimetres. Its width is about 15 millimetres. The head is more flattened than that of Tenia perfoliata, and is destitute of flaps. It carries four round terminal suckers. Tenia Mamillana is the smaller. In length it ranges from ro to 30 millimetres, and its width is about 5 milli- Fig, 12.—~HEApD oF TANIA Fic, 13.—TAnNiA PERFOLIATA. PERFOLIATA. metres. Its head is peculiar—short and broad, and somewhat resembles a rose-bud in shape. The suckers are merely slits, and are laterally placed. Symptoms.—In the horse there is usually little evi- dence to show that Tznia are present in the intestine. Anemia and slight debility may be observed when the number present is very large. Cases of septic peritonitis following perforation of the intestine have been recorded, but must necessarily be very rare. Treatment.—When the presence of tapeworms is 62 VETERINARY PARASITOLOGY demonstrated by their occasional appearance in the feces, treatment is sometimes resorted to. As they are unarmed, there is little difficulty in expelling them. The following draught is usually efficacious : ROL. tereb. ei 2 an ee aij. Creosoti ee sy oa ve (Ole ; Ol. lini .. ad O.j. M. Fiat haust. Male-fern, areca-nut, kamala, and kousso, are other remedies frequently employed by veterinarians. Fic. 14. Heap oF Ta&Nia Fic, 15. —HEAD oF TNIA PLicaTa. MAMILLANA. Ascaris Megalocephala.—This is a large round-worm, of a whitish or yellowish colour, often present in the intestines of the horse. The female ranges from 6 to 13 inches in length, and the males from 5 to 12 inches. The body is stiff and cylindrical, while the head is large, easily visible, and set upon a well-marked constriction, or neck. It carries three lips. The male possesses two wing-like outgrowths—one on each side of the tail. The life-history has been the subject of much investiga- tion. According to Albrecht, ova which are kept in moisture PARASITES OF THE ALIMENTARY TRACT 63 or in dung at ordinary room-tempera- tures require twenty-four to thirty days for the complete development of the embryos, but if incubated at 37° C. three to four days is sufficient. He infers that transmission of the parasite takes place without an intermediate host by ingestion of ova in dung. He fixes the age at which the Ascaris gains sexual maturity as from ten to twelve weeks. Foals are particularly subject to Ascarides, but they occur in horses of all ages. Although no worms may have been passed in the dung, their existence may often be demonstrated by the presence of ova in the faces. They are rounded, and easily visible when a portion of the feeces containing them is mixed with a small quantity of water on a glass slide and exposed to a magnification of roo diameters. Symptoms.—Usually the symptoms are nil, but when large numbers are present anemia and marasmus may result. Intestinal catarrh is often asso- ciated with their presence, and is indi- cated by the discharge of a small quantity of watery fluid after defeca- tion. More uncommon is peritonitis, pro- duced by perforation of the intestinal wall. Jaundice has occasionally been seen, owing to the passage of an Ascaris up the bile-duct, but this is rare. In foals particularly, large numbers of Ascarides not infrequently form a bundle and cause obstruction. Fic, 16.—ASCARIS MEGALOCEPHALA, 64 VETERINARY PARASITOLOGY Nervous symptoms are occasionally seen in the form of epileptiform spasms, vertigo, or even tetanic spasms. Treatment. — Antimony potassium tartrate un- doubtedly stands foremost among the agents employed to expel Ascarides from the horse. One drachm should be given three or four times daily for four days, and followed by a dose of physic. Ol. tereb. is often efficacious, given with creosote and a full dose of ol. lini. Male shield-fern is a well-known remedy, and is usually combined with ol. tereb. and ol. lini. The following is a common prescription for the so- called ‘‘ worm-powders ”’: BR Ferri. sulph. .. Si as ~. 3h. Arsenic ee as oe -- grs. ij. Santonin a ae ts +» grs. Xv. Pulv. gentianz hs a .. §ss. Pulv. anisi ae a cis oe Bh Pulv. locust .. a 3j- M. Fiat pulv. 1. Sig.: To be given in first feed daily. SCLEROSTOMES. These worms are commonly known as “ palisade worms.” They have chitinous mouths, and are thereby capable of doing great damage. Two Sclerostomes may inhabit the intestine of the horse, and both usually exist in the same animal. These are: ‘ I. Sclerostomum armatum or equinum. 2. Sclerostomum tetrvacanthum. Sclerostomum Armatum.—This is a short, straight, stiff worm, of a whitish or greyish-red colour. The female may be known by the straight-pointed tail, and measures about 30 millimetres in length, but this is subject to great variation. The male possesses a caudal pouch, and is about 20 millimetres in length. Occa- PARASITES OF THE ALIMENTARY TRACT 65 sionally specimens are found which greatly exceed this length. In its adult form Sclerostomum armatum inhabits the large intestine of the horse, particularly the cecum, hanging on to the mucous membrane. It may even be found in the duodenum in some cases. Life-History.—Sclerostomum armatum appears in three different positions : 1. Attached to the mucous membrane, or free in the lumen of the intestine. 2. Coiled up in nodules in the submucous tissue. These tumours range from the size of a millet-seed to that of a hazel-nut. They contain the worm, blood, and a quantity of soft, cheesy material. 3. In the arteries (anterior mesenteric or branches of aorta). The eggs are laid either on or in the mucous mem- brane. In the former case the embryo burrows into the mucous membrane. After a while they bore their way out into the lumen of the gut. It is supposed that some, still in an agamous condition, again return and burrow into a vessel. They then work against the blood-stream to the root of the anterior mesenteric artery, and form an aneurism there, or else get into the aorta, and are transported by the blood-stream to other organs. Another theory, which makes the aneurism an essential part of the life-history of the worm, supposes that the ova are deposited in the bowel, and are passed out into damp ground or into water. Some consider that they develop into free Nematodes (rhabditide), and pass this stage of their existence in water or on damp ground. However this may be, the majority agree that after certain moults the embryo gets back into the intestine by ingestion of water or food. Those which bore into the vessels produce an aneurism in which it is believed further development takes place, and they reach their 5 66 VETERINARY PARASITOLOGY full size, after which they again bore back into the intestinal wall, become encysted, and finally reach the lumen of the intestine as the perfect adult parasite. While in the aneurism, the parasite is spoken of as Sclerostomum armatum minor, while the adult is spoken of as Sclerostomum armatum major. Sclerostomum Tetracanthum.—This is a much smaller worm, normally white in colour, but almost invariably bright red, from the blood contained within its body, previously sucked from its host. It ranges from ro to 15 millimetres in length. The mouth is circular, and the rim carries a series of teeth, together with six papille, four large and two small. A little behind these is another pair of long papille, placed laterally. The tail of the male terminates in a caudal pouch, while that of the female is pointed. This worm also inhabits the cecum and colon of the horse, usually in company with Sclervostomum armatum. They are probably taken into the body with the water, and then encyst themselves in the mucous membrane, finally returning to the lumen of the bowel. They do not enter the vessels and set up aneurisms. Symptoms.—Since both of these worms are usually found coexisting in the same horse, it is difficult to draw any marked distinction between the symptoms set up by either worm in particular. Since Sclerostomum tetra- canthum confines itself to the bowel, and seldom bores, it is less frequently the cause of the so-called vermi- nous colic than is Sclevostomum armatum, which does further damage in the vessels. Nevertheless, Sclero- stomum tetracanthum, when present in large numbers, is capable of causing marked anemia, emaciation, and death. The disease is commoner in the country, among horses that have been running at grass, than in town horses, ex- cept in those that have been recently introduced from the PARASITES OF THE ALIMENTARY TRACT 67 country. Colts and young horses are more frequently affected, but it is not at all uncommon to find the worms present in large numbers, often causing grave symptoms, in aged horses. Colts running at grass at first show gradual emaciation, pitched coat, and general signs of unthriftiness. As the disease progresses, weakness sets in, and the colts acquire a stiff gait, particularly behind, and often the joints may be heard to crack, somewhat resembling the sound heard in some rheumatic affec- tions. Ascites is not uncommon, but more frequently one sees cedema of the lips, with swelling of the legs from the hoof upwards. These symptoms arise from circulatory changes. At intervals attacks of colic occur, usually accompanied by diarrhcea and the passage of large numbers of worms. Death may occur during one of these attacks, but more often the colt gets on the ground, and shows inability or unwillingness to rise. In this case death soon supervenes. The attacks of colic are due to cutting off of the blood-supply from portions of the bowel, owing to ob- struction or embolism of small vessels. During the attack the animal usually lies, with the head extended on the ground. The pain is continuous, and may pass off as suddenly as it has come. The colt then stands up, but may appear very dull and stupid for some while after. In older animals Sclevostomum tetracanthum appears to be more commonly the cause of serious trouble than Sclerostomum armatum. The animal shows signs of gradual emaciation, usually with increased appetite, but occasionally the appetite is diminished. The coat stares and the mucous mem- branes are anemic. Ascites is comparatively rare in old horses. We have observed intussusception of the bowel as a result of their presence, though a number of Sclerostomum armatum were present at the same time. 68 VETERINARY PARASITOLOGY In this case the ileum had entered the cecum a distance of 2 feet. The bowels are irregular, usually firm while in the stable, but becoming loose when on a journey. Occa- sionally diarrhoea is persistent. Sometimes micturi- tion is performed more frequently than normal, from irritation. Death may occur from anemia, weakness, and ex- haustion, especially in hard-worked horses. Diagnosis is confirmed by the discovery of the worms in the faeces, especially during the attacks of diarrhoea or after a dose of ol. lini. Prognosis.—This is at all times grave. If treated early the prognosis is much more favourable; but if the animal is on the ground, and unable to rise, then treat- ment is seldom of any avail. When diarrhoea has set in, the danger is much greater. Treatment.—The first essential is rest. Vermicides are of little use, as their dilution is too great when mixed with the contents of the large intestine. Thymol, in our experience, is valueless, although regarded by many as a specific. The only treatment of use is the administration of hematinics over a prolonged period—at least one month —and if the animals are treated early, recovery takes place in go per cent. of cases by this means. The following prescriptions we have found to have produced the best results : HR Ferri ammon. sulph. .. Se .. Bij. Quinia sulph. .. ane 2 +. QYs. XV. Acid. carbol. .. a os -. xv. Pulv. nucis vom. ae a +. gYs. Xx. Pulv. quassize oe ee ea Bie Pulv. digitalis Ss 3 an BTS. Xs Pulv. glycerrh. tie a -» 8]. Theriacze 2 q.s. M. Fiat bol. 1. Sig.: One ball to be given twice daily for one month. PARASITES OF THE ALIMENTARY TRACT 69 & Ferri ammon. cit. .. as se 3h Quin. sulph. .. a +. grs. XV. Acid. hydrochlor. dil. a .. WXV. Tinct. nucis vom. ee Sieg 2. XV. Tinct. digitalis mxv. Tinct. quassize 3ss. Aqua ad O.j. To be peeved every night and morning. Fiat haust. BR Liq. ferri. pee Bij. Thymol : gis. Xx. Spt. vini rect. Biv. Glycerin. 3ij. Ol. tereb. 3iv. Acid. carbol. Mxx. Liq. calcis ox oy ns sg Be OL. lini cae ad 3v. M. Fiat haust. Sig.: To es given in a stat of milk, and repeated once daily. Providing that the animal is not suffering from diarrheea, it is advisable to give the following draught two days before commencing any of the prescriptions mentioned, in order to expel as many worms as possible : ROM. tereb. i ss ee 1. Be Acid. carbol. .. oe is 1. OF. Ol. lini x ae bi .. ad Oj. M. Fiat haust. Ferri sulph. should be avoided, as it is too irritant, and brings on diarrheea. Milk, gruel, eggs, and concentrated, easily digested foods should be given when the disease is at all advanced, particularly if diarrhoea has set in. In verminous or embolic colic the following draught is most useful : BR Spt. ether. nit. ba “% +» 5y.8s. Tinct. digitalis oa . 5-ss. Tinct. chloroformi et morph. acet. 5iij. Acid. carbol. .. te a8 we JBI Lactis .. #e ail a .. ad Oj. M. Fiat haust. 70 VETERINARY PARASITOLOGY Whenever prescribing balls in the treatment of in- testinal parasites, it is well to paint the papers over with a strong solution of salol in ether. The salol is in- soluble in the gastric secretion ; solution of the contents is retarded, and hence the agents employed reach the intestine in a greater degree of concentration. If the diarrhcea becomes acute, mild astringents may be given, combined with sodium sulphite, in doses of I to 2 ounces, as this agent appears to exert a very marked action in checking diarrhcea of verminous origin. Tinct. opii is also very useful. OXYURIDES. The two members occurring in the horse are Oxyuris curvula and Oxyuris mastigodes. Oxyuris curvula is some- times spoken of as the ‘‘ maw-worm.”’ The female ranges from 4 to 5 centi- metres in length. The body is curved, and thickest in its anterior half, while the posterior end tapers away into a very thin tail. The male is rarely seen. It is not curved, has only a short tail, and is only about ro millimetres in length. It possesses a caudal pouch and a very fine, straight spicule. Fig, oo Oxyuris mastigodes differs from URVULA. 3 5 Oxyuris curvula in the remarkable length of its tail. Whether it is but an abnormal form of the former worm has been disputed. The Oxyuride inhabit the large intestine, more especially the floating colon, rectum, and diaphragmatic flexure of the double colon. The eggs are deposited in the neighbourhood of the anus in the form of a yellow PARASITES OF THE ALIMENTARY TRACT 71 dust. Each egg is ovoid, about go p» long, and provided at one end with an operculum. Symptoms—These are often absent. When the worms are present in large numbers there is seen frequent rubbing of the anus and tail, with the presence of the characteristic yellow dust around the anus. Occasionally there is loss of condition from irritation and loss of rest. Oxyuris mastigodes appears to cause more disturbance than Oxyuris curvula. Life-History—This has not been fully worked out. Probably there is no intermediate host, but infection by ingestion of ova. Treatment.—Turpentine and linseed-oil given once a week or once a fortnight, with early-morning clysters of infusion of quassia or common salt, given after the rectum has been emptied by hand, usually eradicate these parasites. The ‘‘ worm-powders,” of which the prescription was given when referring to Ascarides, are very useful. Trematodes occurring in the Horse. These are two in number: 1. Amphistomum Collinst. 2. Gastrodiscus Algyptiacus. Amphistomum Collinsi (Masuri).—This is a worm of a brick-red colour occurring in immense numbers in the large intestine of horses in India. They produce great irritation. Gastrodiscus Higyptiacus (Gastvodiscus Sonsinoi, Gas- trodiscus Polymastos).—This parasite has a red, oval body, about 12 millimetres long, convex on the upper or dorsal and flat on the ventral surface. The buccal sucker is carried on a short proboscis, while the ventral surface carries about 200 papillary suckers. It inhabits chiefly the small intestine of horses, asses, and mules in Egypt and Senegal, but may occur in 72 VETERINARY PARASITOLOGY almost any portion of the alimentary tract. It produces anemia and marasmus. Treatment consists in giving vermicides and purgatives. All land should be limed or salted, and drinking-water filtered through fine sieves. PARASITES INHABITING THE ALIMENTARY CANAL OF THE OX. Ganglyonema scutatum is sometimes present in the cesophagus of the ox. Stomach. Amphistomum conicum, a Trematode, may inhabit the first stomach. It seldom produces noticeable symp- toms, except in Australia, where the parasite appears to possess exceptional virulence. Various Strongyles may inhabit one or other of the stomachs. Hence Strongylus contortus, Strongylus gracilis, and Sivongylus convolutus may be found in the abomasum. These will be discussed more fully later. Ascaris Vitulorum is sometimes seen in the abomasum of the calf, but more frequently in the small intestine. It is a large worm, the female reaching the length of 25 centimetres (ro inches), and the male about 20 centi- metres (8 inches). It is of a reddish-white colour, with a transparent skin. The head is small, and the mouth trilabiate. It is rare in animals over two years old, but is comparatively common in the small intestine and abomasum of calves, particularly in the South of France. The embryos are the more active in producing the disease. The commonest symptoms are those of colic and indi- gestion. A few worms may be passed with the feeces. Perforation or rupture of the abomasum has frequently been recorded. Treatment.—Calomel, areca-nut, turpentine, and lysol are favourite remedies, and should he followed by linseed-oil or saline purgatives, PARASITES OF THE ALIMENTARY TRACT 73 Small Intestine. CESTODES OF THE OX. The three tapeworms inhabiting the ox belong to the Anoplocephaline, or unarmed worms. These have the genital pore double in each segntent, all of which are much broader than long. The three tapeworms are: I. Tenia expansa. 2. Tenia alba. 3. Tema planissima. Tenia Expansa.—This is the commonest and also the largest tapeworm of the ox. It ranges in length from Fic. 18,—HEAaAD oF T2NIA Fic. 19.—HEAD oF TANIA EXPANSA. ALBA. 25 to too feet. The anterior segments are narrow, but the ripe posterior segments are very short, and are usually an inch wide. The head is small and slightly flattened, and the suckers are arranged in the form of four oval slits. Tenia Alba.—Next to Tenia expansa, this is most commonly found. It averages about 6 feet in length, and the widest segments reach from $ inch to 2inch. The segments are proportionately longer than those of Tenia expansa, and are of a dense whiteness. On holding the 74 VETERINARY PARASITOLOGY worm between the eyes and the light an opaque line may be seen running the whole length of each segment, about $ inch from the edge. The head is large, and extends beyond the adjoining segments, while the suckers, unlike those of Tenia expansa, are round. Tenia Planissima, or Denticulata.—This worm ranges from 3 to 6 feet in length only, and is characterized by a serrated edge, which is due to the overlapping of each anterior segment. The head is by no means large, and the suckers are slightly elongated. 5 Symptoms.—The presence of | tapeworms in the ox is seldom suspected until some have been passed with the feces. If in large numbers, they may cause anemia, loss of condition, depraved appetite, and diarrhcea. By coiling them- Fic. 20.—Hzap oF selves together into a ball, they Tania DENTICULATA. : : : may cause intestinal obstruction. Treaiment.—As these worms are unarmed, vermicides and purgatives will remove them with little difficulty. Lysol, turpentine, male-fern, areca-nut, given in linseed-oil, are quite efficient. Arsenic, in doses of ro grains daily, may be given to oxen for three or four consecutive days. Strongylus Ventricosus.—This worm is the inhabitant of the small intestines of cattle and deer. It is a com- paratively small worm, the female reaching only 12 millimetres in length, and the male 6 to 8 millimetres. In the male there is a broad caudal pouch, which is not distinctly trilabiate. In the female the vulva is situated just behind the middle of the body, and is surrounded by a pouch. Professor Penberthy has associated this worm with cases of parasitic gastro-enteritis in cattle and sheep, while other observers regard it as producing no ill-effects. - = SS PARASITES OF THE ALIMENTARY TRACT 75 CESOPHAGOSTOMES. Gisophagostomum Columbianum.—This parasite is the cause of the so-called “‘ pimply gut,’ which is more common in America. It is occasionally seen in this country, infection taking place through the spreading of manure brought from other countries. The male is } inch and the female 3 inch long. The whole of the life-history is unknown. The eggs are laid in the intestine, and pass out with the feeces. The embryos are found in small tumours, from the size of a pin’s head to a pea, under the mucous membrane. They possess no boring apparatus, so that some doubt exists as to the precise manner in which they gain their position. In these nodules the embryo moults, and develops until it reaches about 3 inch in length, when the nodules burst, and the worm is set free. The intestines must not be used for preparing sausage- skins. Csophagostomum Inflatum is not so common. STRONGYLES INHABITING THE ALIMENTARY CANAL OF CATTLE, SHEEP, AND DEER. These are of especial importance, as they cause very serious wasting disease, accompanied by great mortality. The Strongyles inhabiting the stomach and intestine of ruminants are: Strongylus cervicornis. Strongylus contortus. Strongylus filicollis. Strongylus vicarius. Strongylus MacFadyensis. Strongylus convolutus. Strongylus gracilis. WOYRONH 76 VETERINARY PARASITOLOGY To detect the presence of these worms after death, the abomasum or a piece of intestine should be opened and emptied of its contents. A scraping of the mucous mem- brane should then be taken and mixed in a watch-glass with water, placed while in this receptacle on the stage of a microscope, and examined with a low-power objective. A magnification of x50 is ample. If the watch-glass is placed on a piece of black paper, in a good light, the parasites may be more readily discovered. In addition to the adult worms, ova and embryos may be discovered. A brief description of the more important of the above-mentioned parasites will suffice. Strongylus Cervicornis inhabits the abomasum of cattle and the intestine of sheep and lambs. It causes great mortality—even as high as 20 per cent. Its colour is a greyish-white. The male is 7 millimetres long. It has a caudal bursa, supported by dichoto- mously branched chitinous rays. The female is ro millimetres long. Strongylus Contortus inhabits the abomasum of cattle and sheep. It is of a reddish colour, owing to the blood of its host contained within it. The male is ro to 20 millimetres in length, and the female ro to 30 millimetres. The male has a bilobed caudal bursa, with a small unilateral accessory lobe. The oviducts of the female are contorted, and wound around the intestine. Strangylus Filicollis inhabits the abomasum of cattle and sheep, and commonly the small intestine. The anterior portion is tapered into a neck. It is smaller than Strongylus contortus. Strongylus MacFadyensis is similar, but smaller. Strongylus Convolutus inhabits the abomasum of cattle and sheep. The male has a bilobed caudal bursa, with four rays in each. PARASITES OF THE ALIMENTARY TRACT 77 This worm lives coiled up in nodules in the mucous membrane. Strongylus Gracilis affects cattle, sheep, horses, and pigs. It is dull white in colour. It possesses a tapered anterior extremity, like Stvongylus filicollis, but is smaller. The female is only 3 to 4 millimetres in length. Symptoms.—Parasitic gastro-enteritis is more often seen in young animals, such as yearling cattle and lambs, especially when a wet winter follows a dry summer. It is characterized by progressive emaciation, diarrhoea, and anemia. Young cattle affected show all the symptoms of catarrhal gastritis and enteritis. Diarrhoea is a marked symptom, and wasting is very rapid. The feces are watery, black, and foetid. The animals refuse food, but exhibit great thirst, and show signs of stomach irritation, such as licking sand or soil. The temperature is elevated, and 105° or even 108° F. is by no means uncommon. The cattle appear tucked up and hidebound, and the mucous membranes are pale and anemic. Finally, the temperature becomes subnormal, and death takes place from exhaustion. The course of the disease is usually from one to three weeks, but may be only from one to three days. In sheep the disease presents similar symptoms, but the mortality is even greater. It is extremely common to find husk present at the same time. Lesions.—On post-mortem examination, the mucous membranes of the abomasum and small intestine are found in a condition of catarrhal inflammation. Ulcera- tion may be present, or the mucous membrane may be easily removed by slight friction. A submucous gela- tinous exudate is commonly present. 78 VETERINARY PARASITOLOGY The external mucous membranes are anemic. Ascites is occasionally seen. On making a microscopical examination, hundreds of Strongyles may be discovered. Prognosis.—Animals badly affected with parasitic gastro-enteritis seldom recover unless treated, and even then with difficulty. Prophylaxis—The parasites which cause these symp- toms must necessarily pass a certain period of their existence amid damp surroundings, and they undergo certain modifications outside the host. All affected pastures should be drained, salted, limed, or ploughed. If possible, they should be kept free from cattle. Overcrowding must be avoided, and lambs and yearlings should be well fed and kept in good condition, in order that they may withstand the attacks of Strongyles. As preventives, salt and general tonics may be given in the food. Lambs must never be placed on affected ground after adult sheep, as the latter may act as a host and yet be unaffected, and may pass the disease on to younger animals, with disastrous results. Treatment.—Afiected animals should be isolated, and the whole herd or flock dosed, as a preventive measure, three times, at intervals of three days. The following drench is suitable for lambs : R Ol. tereb. Chloroformi } Lysol fe M. Fiat haust. Sig.: To be given in milk. sy J. or go Mx. Picrate of potash, up to 5 grains per lamb, is also very successful. In cattle lysol has proved most useful. As a prelimi- nary 4 drachms may be given, either by bottle or probang. PARASITES OF THE ALIMENTARY TRACT 79 Professor Penberthy recommends the following : BR Lysol ie i “5 +. Bij. Chloroformi .. ae La -» Bij. Ol. tereb. be : a (B) Measles of Pork. This condition arises from the presence of Cysficercus cellulose. This is a small ovoid cyst, about 15 milli- metres long and 73 millimetres wide. It shows, when magnified, a white spot, corresponding to the invaginated head. If the head is extruded by pressure, it may be seen to be four-sided, and to carry four suckers and a rostellum, bearing a double row of hooks, twenty-four to thirty-two in number. The Cysticerci may be found in any or all the striped muscles, but the muscles chiefly affected are, in order: PARASITES OF MUSCLE 119 the tongue, cervical muscles, muscles of the shoulder, pillars of the diaphragm, intercostal muscles, psoas muscles, muscles of the thigh. The myocardium is also frequently affected, as are also various organs of the body. The muscles containing the Cysticerci are flabby and pale in colour, and contain small cavities, which lodge the parasites. On section, the flesh is wet, and, if badly affected, a yellowish clear fluid may exude. In pork that has been measly for a considerable length of time the Cysticerci become calcified. Symptoms.—Usually symptoms are not recognizable during life. When very advanced, there may be diffi- culty in muzzling, loss of energy, anorexia, diarrhoea, stomatitis, and death. The Cysticercus cellulose of the pig, when ingested by man, develops in the intestine into Tenia solium. The worm becomes mature about two months later. The flesh, when eaten, is gritty and sweet to the taste. Roasting at 120° F. for one minute kills the parasite, but this temperature is not usually reached in the centre of pork while being cooked for the table, though the ex- ternal temperature may be 212° F. In smoked hams and pickled pork the vitality of the Cysticerci is usually weakened. Measles of Beef. This condition is produced by the presence of Cystz- cercus bovis in the muscles of the ox. This is an ovoid cyst, measuring from 3 to 15 milli- metres in length. It shows a small, dense, yellowish area at one point, corresponding to the invaginated head. When extruded, the head presents the characters of that of Tenia saginata of man, tetragonal in shape, devoid of hooks, and possessing four large rounded suckers. 120 VETERINARY PARASITOLOGY These Cysticerci may be found in any organ, but voluntary muscles are usually affected. The most common site is in the muscles of mastication —the masseter, pterygoids, and in the tongue.. Then, in order, follow the heart, gluteal, intercostal, cervical, psoas, and pectoral muscles. The Cysticerct bovis are never present in such numbers as are the Cysticerci cellulose, and, moreover, they quickly become calcified. Symptoms.—Usually nil. When ingested by man, the Cysticercus develops into Tenia saginata in the intestine. TRICHINOSIS. This is the name applied to the condition arising from the presence of Tvichina spiralis in the body of the pig or man. Trichina spivalis is a member of the family Tricho- trachelide. : The adult male worm is about 1 to 5 millimetres in length, and the female 3 to 4 millimetres. They possess very slender bodies, tapering at each end, with no trans- verse striation. The female is ovoviviparous. LirE-History.—The adult stage is passed in the intes- tine and the larval stage in the muscles. When flesh infested with encysted larve has been ingested by a suitable animal, more especially the pig, or even man, the cysts become partially digested and the larvee are set free. After an interval of a few days, they develop into sexually mature Trichine, copulate, and the females soon deposit embryos. The number produced by a single female at one ovulation may exceed 10,000. The embryos then proceed to migrate to the muscles, either by boring through the intestinal wall or by the aid of the blood or lymph streams. The average PARASITES OF MUSCLE 121 interval between ingestion of trichinous meat and muscle infestation is ten days. On arriving at its destination, each larva coils itself into a spiral, and by its presence irritates the tissues, so that eventually fresh connective tissue is thrown out from that already between the bundles of muscle fibres, and a cyst wall is formed around the parasite. Each cyst is somewhat ovoid and pointed at the extremities, and in its length lies parallel with the direc- tion of the muscle fibres. The length of the cyst is from 0-3 to o-8 millimetre. The commonest seats of infestation are : Pillars of diaphragm. Muscles of tongue and larynx. Shoulder. Intercostals. Psoas muscles. Adductors of thigh. DUR Y NH The muscles are infested to a greater extent close to their insertions. In order to discover Trichina cysts in pork, thin strips are cut from the pillars of the diaphragm, tongue, etc., in the direction of the muscle fibres. These should be macerated in a mixture composed of pot. chlor., 1 part, and acid. nitric. dil., 4 parts. The strips are then shaken in water, placed between two slides, and examined micro- scopically. The coiled-up larva is then easily visible. When trichinosis has been present for a long time calcareous or fatty degeneration sets in, and in the former case the cyst becomes hard, and gives a gritty feel to the meat. Pigment may also be deposited in the cyst. Calcareous and fatty deposits usually render the parasite harmless. Symptoms.—In the pig symptoms are usually absent. If the number of invading Trichine is large, the first 122 VETERINARY PARASITOLOGY symptoms noticeable are those of enteritis. There may be anorexia, fever, thirst, grinding of the teeth, with tucked-up flanks and arching of the back. Chronic diarrhcea then sets in. About the tenth day these symptoms diminish and give way to muscular symptoms. The animal is stiff and has difficulty in walking. The muscles are sore to touch, and the pig usually remains in the recumbent position. The animal may now re- cover or become dropsical and eventually die. InFEcTION, ETC.—Infection takes place in the pig from ingestion of trichinosed flesh, such as that of rats, which are frequently affected, or from devouring the excreta of animals containing Trichina in some stage of their life-history. Probably the pigs infect the rats, and vice versa, and so the existence of the disease is main- tained. In Germany, America, Holland, Denmark, and Sweden, and particularly in Russia, trichinosis in man is not rare, owing to the practice of eating only partially cooked pork. VitaLity.—Boiling affected pork for fifteen minutes per pound weight is considered safe, and experiment has shown the Trichina to be destroyed by this means. Roasting, if complete, is sufficient to destroy the parasites. Salting and smoking are not reliable. Putrefaction has little influence on their vitality, and after four months some Trichine may yet be alive. PARASITES AFFECTING THE EYE. Numerous parasites may affect the eyelids. Among these are Acari, Demodectes, and the Pediculide. Besides these, various Diptera attack theexterior of the eye, especially the nasal canthus. Filaria Pellucida.—There is some doubt as to whether this worm may not be an undeveloped stage of Filaria PARASITES AFFECTING THE EYE 123 papillosa. It is commonest in the horse, and is met with in India, Burma, and Ceylon. It is a fine thread-like, reddish-white worm, somewhat thicker in front. The male is about 30 millimetres in length, and the female is slightly smaller. The habitat of this parasite is the anterior chamber of the eye. Both eyes are seldom affected simultane- ously, and there is usually only one worm present, but three is not an uncommon number. Symptoms.—Conjunctivitis and swelling of the eye- lids are present, arising from irritation. Photophobia is very marked. In the early stages the worm may sometimes be seen through the cornea. Later opacity sets in. ‘‘ Loin-weakness”’ has been associated in India with the presence of the Filariain the eye. TREATMENT.—Cocaine is applied, and the cornea punctured with a cataract needle. The worm is thus brought into the wound by the rush of aqueous humour, and is withdrawn. A larval form of Filaria cervina infests the eye of the ox in a similar manner. Similar parasites have been observed in sheep, dogs, and poultry. Filaria Palpebralis—A white filiform worm, from 8 to 16 millimetres in length. , It has been found in the lachrymal sac and in the conjunctiva beneath the eyelid. Filaria Lachrymalis.—This is a longer worm, Io to 24 millimetres in length. It affects the eyelids of cattle in the South of France in a similar manner. TREATMENT.—This consists in removing the parasites, and applying mild astringents and sedatives to lessen the conjunctivitis. APPENDIX I In advanced cases of the pustular type we have lately obtained almost remarkable results from the following treatment : The largest pustules are first squeezed out and the affected areas dressed once or twice, at intervals of a day, with the following mixture : B Formalin 24 a a a dij. Glycerin : a3 a a2 Bi. Spts. vini rect. £4 8 .. Bij. Ol. caryoph. .. oe .. Biij. Ol. rapii a 2% i .. ad 3vj. M. Fiat. lin. This application at first produces marked hyperemia and swelling of the skin. After one or two dressings the pustules appear flat- tened, dry, and scaly, and the majority soon disappear, leaving the skin smooth and apparently healthy. The parts are then dressed with Ung. sulph. co. until they are thoroughly softened, and then treated daily with the following : R Formalin $i fs are Ps ass. Glycerin a 2 .. Bh Tinct. cantharid. Ae ne .. 3iss. Acid. salicylic. Ra 2% .. 58s. Spts. vini rect. at re beh, VSO Ol. ricini ie ea a .. 5ij. Ol. rapii oe as os -. ad 3vj. M. Fiat. mist. 124 APPENDIX 125 The hair soon commences to grow, and in the great majority of cases thus treated by us a perfect cure has resulted, although many have at first appeared hopeless. APPENDIX II By the Sheep Scab Order of rgr1o, recently issued, Article 5 of the Sheep Scab Order of 1905 is revoked, and an article substituted which enacts that for the prevention of scab an inspector of the Local Authority shall serve an Isolation Notice on the owner or person in charge of sheep recently affected or in any way suspected of scab or exposed to infection, and that such sheep shall not be permitted to stray or come into con- tact with other sheep until a further notice has been issued. It further enacts that if, on veterinary inquiry, the above suspicions are found to be correct, the sheep shall be efficiently dipped by the owner, and, if requred, in the presence of the inspector. By an amendment of Article 9, a Local Authority may make regulations requiring the dipping of sheep moved from another district into their district (providing they remain there over seven days), and may also issue notices regulating their movements, and requiring an owner to notify the arrival of sheep. Paragraph 4 of Article 30 is omitted, and a notice substituted forbidding the straying of sheep, in con- travention to the order, under penalty. IN ACANTHOCEPHATLA, 56 Acariasis, psoric, 8 non-psoric, 33 Acarina, 8 Achorion, 2, 3 quinckeanum, 6 Amblyomma Hebreum, 36 Amphistomum Collinsi, 71 conicum, 72 tuberculatum, 79 Ankylostomum trigonocepha- lum, 95 Annelida, 50 Aphaniptera 43 Aptera, 37 Ascaridee, 54 Ascaris marginata, 94 megalocephala, 60, 62 miystax, 95 ovis, 82 suis, 84 vitulorum, 72 Autumnal breeze-fly, 45 Balbiania gigantea, 117 Bilharzia crassa, 53, I14 Boophilus, 33 Bothriocephalus latus, 91, 86 cordatus, 86 felis, 93 fuscus, 86 Bots, 57 Brachycera, 43, 44 Breeze-flies, 44 Bronchial strongyles, 108 Bronchitis, verminous, IIT Broncho-pneumonia, vermin- ous, III pseudo tuberculous, 111 DEX Cestodes, 52 Chorioptes, 9 Coccidia, 79, 106 in the liver, 97 Coccidium Zurni, 80 oviforme, 80 cuniculi, 98 Ccenurus cerebralis, 91 Culicide, 43 Cutaneous filariasis, 41 Cysticercus Bailleti, 113 cellulose, 115 fasciolaris, 93 pisiformis, $8, 98 tenuicollis, 88 Demodecide, 9, 21 Demodectic mange, 21 Demodex folliculorum, II, 21 Diptera, 43 Dipylidium caninum, 86, 91 Distomata, 53 Distomum hepaticum, 99 albidum, 105 felineum, 105 heterophyes, 105 lanceolatum, 99, 100 truncatum, 105 Dracontiasis, 42 Echinococcus cyst, 87 veterinorumi, go, 98 Echinorhyncus gigas, 56, 83 Eustrongylines, 5 Fascioliasis, 99 Favus in sucklings, 5 in dog and cat, 6 multipapillosa, 41 126 INDEX 127 Filaria cervina, 114 equina, 113 heemorrhagica, 41 immitis, 115 irritans, 42 lachrymalis, 123 Medinensis, 42 palpebralis, 123 papillosa, 113 pellucida, 122 Filariidee, 54, 55, 57 Fluke disease, 99 Follicular mange in the dog, 2 in the pig, 24 ‘*Formication,”’ 23 Ganglyonema scutatum, 60, 72; 83 Gastrodiscus, 53, 71 Hi gyptiacus, 71 polymastos, 71 Sonsinoi, 71 Gastrophilus equi, 57 heemorrhoidalis, 58 nasalis, 59 pecorum, 55 Glossina morsitans, 45 Hemaphysalis Leechi, 36 punctata, 36 Heematobia, 45 Hematopinus, 37 eurysternus, 38 macrocephalus, 38 pedalis, 38 piliferus, 38 tenuirostris, 38 urius, 38, 39 vituli, 38 Heematopota, 45 pluvialis, 45 Heematozoon Lewisi, 115 Hemopis sanguisuga, 50 Helminthes, 50 Hippobosca al 48 rubipes, 4 Hippoboscide, 43, 44, 45, 48 Hirudo medicinalis, 51 Hypoderma bovis, 46 equi, 47 Intestine, protozoa inhabiting the, 79 Ixodes, 33, 34 plumbus, 36 reduvius, 36 ricinus, 36 Ixodide, 33 Leptus autumnalis, 36 Limnea trunculata, IoI Lingulatula denticulatum, 97, 107, 114 teenioides, 97, 106 Liver rot, 98 “ Lousiness,’’ 37 Tucilia, 45 Ceesar, 49 macellaria, 49 sericata, 49 Mange, 8 follicular, 21 in the cat, 19 in the dog, 18 sarcoptic, in the pig, 26 symbiotic, in dogs and cats, 20 Mange in cattle, 17 psoroptic, 17 sarcoptic, 17 symbiotic, 17 Mange in sheep, 26 psoroptic, 27 sarcoptic, 26 symbiotic, 32 Mange in the horse, 12 psoroptic, 14 sarcoptic, I2 symbiotic, 15 Measles, 118 of beef, 119 of pork, 118 Melophagus ovinus, 49 Mesocestoides lineatus, 86, 92, 93 Microsporon, 2, 3, 4, 6 Miescher’s tubes, 117 Monostomum hepaticum, 105 Muscide, 44, 45, 49 128 VETERINARY PARASITOLOGY Nemathelminthes, 52, 53 Nematodes, 52, 54 Nematoidea, 54 Nemocera, 43 Non-psoric acariasis, 33 Nose, parasites of, 107 C¥sophagostomes, 75 , Csophagostomum Columbia- num, 75 inflatum, 75 CGistridze, 44, 45, 46 Cistrus equi, 57 CHstrus ovis, 48, 107, Ollulanus tricuspis, 85 OGspora canina, 6 Ox breeze-fly, 45 Oxyuridee, 54, 55 Oxyuris curvula, 70 mastigodes, 70 Parasites, vegetable, 1 Parasitic granular dermatitis, 42 Pediculidee, 37, 122 Pediculine, 37, 122 Phthiriasis, 30, 37 Platodes, 52 Platyhelminthes, 52 Protozoa inhabiting intestine, 79,85 Psoric acariasis, 8 Psoroptes equi, 14 Psoroptic mange in horses, 14 in cattle, 17 in sheep, 27 Pulicide, 40 Pupipara, 42, 48 Rain-rot, 29 Rhipicephalus, 33 annulatus, 36 appendiculatus, 36 Australis, 36 bovis, 36 bursa, 36 Ricinidze, 37 Ringworm, I in the dog and cat, 6 in the horse, 4 in the ox, 6 Sarcocystis Miescheri, 118 tenella, 118 Sarcophaga magnifica, 49 Sarcoptes, 9 Symbiotes, 9, 10 equi, 12 minor, 19 ovis, 26 squamiferus, 18 suis, 26 . Sarcoptic mange in cattle, 17 in the cat, 19 in the dog, 18 in the horse, 12 in the sheep, 26 Sarcoptide, 8 Sarcosporidize, 117, 118 Sclerostomum armatum, 64, II4 armatum minor, 66, 114 hypostomum, 82 tetracanthum, 64, 66 Sclerostomines, 56 Sclerostomum, pinguicola, 114 Serous membranes, parasites of, 113 Sheep scab, 27 Simuliide, 43 Spiroptera, 57 megastoma, 57 microstoma, 57 reticulata, 116 sanguinolenta, 85 Stomoxys calcitrans, 45 Strongyles, bronchial, 108, 116 Strongylide, 54, 56 Strongylines, 56 Strongylus axei, 57 cervicornis, 75, 76 contortus, 72, 75, 76 convolutus, 72, 76 filicollis, 75, 76 gracilis, 72, 75, 77 MacFadyensis, 75, 76 ventricosus, 74 Strongylus filaria, ro9, 110 Armfieldii, 109 commutatus, 10g micrurus, 109, ITo paradoxus, 109 pucillus, 109 INDEX Strongylus pulmonalis, 109 rufescens, Icg, I10 vasorum, I16 Sucklings, favus in, 5 ‘«Sumimer sores,’’ 42 Symbiotes auricularis, 20, 32 bovis, 17 Symbiotic mange in cattle, 17 in dogs and cats, 20 in the horse, 15 Tabanidee, 43, 44 Teenia alba, 73, SI ccenurus, crassicollis, 93 cucumerina, 52, 91 cysts in the liver, 98 denticulata, 81 echinococcus, 86, 89 elliptica, 93 expansa, 73, 81 fimbriata, 81 Krabbei, 86, gt litterata, 52 mamiillana, 60, 61 marginata, 52, 86, 88 perfoliata, 60 planissima, 73, 74 plicata, 60, 61 saginata, 119 serialis, 86, 90 serrata, 86, 87, 88 solium, IIg Teenioide, 52 THE 129 Tapewornis in sheep, 81 Thysanosomum actinioides, 81 Ticks, 33 Trematodes, 52, 53 in the liver, 97 of the horse, 71 Trichina, 55 spiralis, 120 Trichinosis, 120 Trich: cephalus, 55 affinis, 79 crenatus, 85 Trichodectes, 37 latus, 38 pilosus, 38 pubescens, 38 scalaris, 38, 39 sphzerocephalus, 38 subrostratus, 38 Trichophyton, 2, 4, 6 mentagrophytes, 4 tonsurans, 4 Trichotrachelide, 54, 55 Trombidiide, 33 Trombidium holosericeum, 36 Tsé-tsé fly, 45 Vermes, 50 Verminous bronchitis, 117 broncho-pneumonia, III pseudo-tubercular, 111 Worm aneurism, 65, 114 Worm colic, 67 END Bailliére, Tindall ana Cox, 8, Henrietta Street, Covent Garden ene erat cae ge inti re hin ES pe reecen nce als Seem alenMEn sane no o i jee lll EE ft hal uf ANE