U. S. DEPARTMENT OF AGRICULTURE, 
 
 BUREAU OF ANIMAL INDUSTRY.— Bulletin No. 66-' 
 D. E. SALMON, D. V. M., Chief of Bureau. 
 
 S F 
 
 968 
 
 Tv2Z 
 
 THE GID PARASITE {CCENUBUS CEREBRALIS) 
 ITS PRESENCE IN AMERICAN SHEEP. 
 
 BY 
 
 B. H. RANSOM, B. Sc, A. M., 
 
 Scientific Assistant in Cliar^re of the Zoological Laboratory, 
 Bureau of Animal Industry. 
 
 WASHINGTON: 
 
 GOVERNMENT PRINTING OFFICE. 
 1905. 
 
 ^mnf^t^ 
 
Class. 
 Book_ 
 
/ c^ 
 
 U. S. DEPARTMENT OF AGRICULTURE, 
 
 BUREAU OF ANIMAL 1 NDUSTRY.— Bulletin No. 66. 
 
 D. E. SALMON, D. V. M., Chief of Bureau. 
 
 ^^ 
 
 THE GID PARASITE {CCENURUS CEREBRALIS): 
 ITS PRESENCE IN AMERICAN SHEEP. 
 
 BY 
 
 B. H. RANSOM, B. Sc, A. M., 
 
 Scientific Assistant in C/iarge of the Zoological Laboratory , 
 Bureau of Animal Industry. 
 
 WASHINGTON : 
 
 GOVERNMENT PRINTING OFFICE. 
 1905. 
 
^ 
 
 
 V 
 
 ''I'o?^,^ 
 
LETTER OF TRANSMIITAL 
 
 U. S. Department of A(tRIculture, 
 
 Bureau of Animal Industry, 
 
 Sir: I have the honor to transmit herewith a manuscript entitled 
 *'The Gid Parasite {Oinxrm cti^ebml/K): Its presence in American 
 Sheep," by B. II. Ransom, B, Sc, A. M., scientific assistant in charge 
 of the zoological laboratory of this Bureau. 
 
 This parasite in its bladderworm stage ( C<ef> unis cerehr(fh'.'<) cnusen 
 the disease called gid, otherwise known as "sturd}'," "staggers," etc., 
 which principally affects sheep, although cattle and other herbivorous 
 animals are also susceptible. It is transmitted to stock through pasture 
 or water which has been contaminated b}' the eggs of a certain species 
 of tapeworm {Txnla camurus) parasitic in the intestines of dogs, the lat- 
 ter having acquired the parasite by feeding upon the carcasses of stock 
 infested with the bladderworm stage. Although a common disease 
 in Europe, where it frequently- occasions losses of fully 10 per cent 
 in flocks of sheep, gid has until veiy recently been unknown in the 
 United States. Early in the present year, however, a well-authen- 
 ticated outbreak occurred in the sheep-grazing regions of the West, 
 and it was, consequently, deemed expedient to publish such facts as 
 would help our stockmen to protect themselves against possible out- 
 breaks in the future. 
 
 The information concerning gid herein set forth is of nuich practical 
 importance to sheepmen, as it enables them to recognize the disease 
 should it make its appearance, and indicates the measures best calcu- 
 lated to prevent its spread. I therefore recommend that the work be 
 published as Bulletin No. 6«> of the series of this Bureau. 
 Respectfullj% 
 
 D. E. Salmon, Chief of Bureau. 
 
 Hon. James Wilson, 
 
 Secretary of Agriculture. 
 
C N T 1: X T S . 
 
 Page. 
 
 Introduction 7 
 
 Presence of gid in the United Staten 8 
 
 Historical review of gid 8 
 
 Economic importance of gid *) 
 
 Description of the gid l)ladderworm ( Cotnurus ceri'hralis) 10 
 
 Description of the gid tapeworm ( Tamia cmmrm) 12 
 
 Life history of the gid parasite 14 
 
 SusceptibiHty of sheep and other animals '. 16 
 
 Symptoms — 
 
 Cephalic gid 1 «} 
 
 Medullary gid 17 
 
 Pathology 17 
 
 Diagnosis 20 
 
 Treatment 20 
 
 Prevention 20 
 
 USTRATIONS. 
 
 Page. 
 
 Fig. 1. Gid bladderworm ( Crenurn^ cereliralts), showing the heads 10 
 
 2. Diagrammatic section of a gid bladderworm 11 
 
 3. Larval tapeworm head dissected away from the wall of a gid bladder- 
 
 worm 11 
 
 4. Hooks from the gid bladderworm 12 
 
 5. Hooks from a l)la(lderworm of the rabbit ( C(r)i;nrtis serlali.^) 12 
 
 fi. Portions of an adult gid tapeworm ( Tirnla ca'nnrns) 13 
 
 7. Sexually mature segment of the gid tapeworm 13 
 
 S. Gravid segments of tapeworms of dogs, showing the median stem of 
 
 the uterus and its lateral Ijranches 14 
 
 9. Gravid segment of Ts-n'ia serialis, a tapeworm (if dogs often confused 
 
 with T. cfenums 15 
 
 10. Brain of lamb showing the furrows produced by the migration of 
 
 young gid bladderworms 15 
 
 11. Skull of a sheep showing the brain infested with a gid bladderworm. . 18 
 
 12. Sheep's skull, showing perforations resulting from the jiresence of gid 
 
 blad«lerworms U) 
 
 5 
 
THE GID PARASITE (C(ENURUS CEREBRALIS): 
 ITS PRESENCE IN AMERICAN SHEEP. 
 
 By B. H. Ransom, B. Sc, A. M., 
 Scientific Assistant in Charge of Zoological Laboratory, Bureau of Animal Industry. 
 
 INTRODUCTION. 
 
 The disease popularl}" known by English-speakino- peoples as gid, 
 sturd}^ staggers, turnsick, etc., which affects sheep, and, more rarely, 
 cattle and other animals is a common disease of stock in Europe. It 
 is said to occur also in South America, and is now known to occur in 
 this country. The cause of this disease, a characteristic sj'mptom of 
 which is vertigo and turning of the affected animal, is the presence of 
 a parasite, the gid bladderworm (tig. 1), in the brain or spinal canal. 
 
 The gid bladderworm, or Cmiurns cet'ebralis as it is known technic- 
 ally, is the larval stage of a tapeworm, Tivnia C(enuri(i< (tig. 6), which is 
 found in the intestines of dogs. When the brain of a "gidd}'" sheep 
 is eaten by a dog, the bladderworm develops into tapeworms in the 
 intestines of the latter. The tapeworms produce eggs, which pass out 
 of the dog's intestines and fall to the ground, where they maj' lie amid 
 the grass or be washed by rains into pools of water. Sheep and cattle 
 while grazing or drinking ai"e liable to swallow these eggs, which 
 tiien hatch out, and the embr3^os, boring out of the intestines, wander 
 to the brain or spinal cord, where they undergo further development 
 and give rise to the condition known as gid. 
 
 It seems reasonable to suppose, in view of the large numbers of sheep 
 and dogs which have been imported into the United States from coun- 
 tries where gid is common, that the disease should have become more 
 or less prevalent here also, but for some reason the gid parasite has 
 never gained a foothold in North America, and until veiy recently, so 
 far as it has been possible to determine, gid has been entirely unknown 
 in this countiy. A possible exception ma}- V)e based on the mention 
 made by Leidy (1856) of '"''Co&nurus cerebraUs Rud. in the sheep, 6'(2j>r« 
 artes^'^ but neither the time nor the place of the collection of the 
 specimens referred to l)v that author is known. Although heretofore 
 no cases of gid in this country have been placed on record, it seems 
 hardly probable, in view of our present knowledge, that the disease 
 
 7 
 
8 BUREAU OF ANIMAL INDUSTRY. 
 
 has been altogether absent. jSIore likely, oases have occurred from 
 time to time and passed unrecognized, as evidence has come to hand 
 which shows that the disease is now present in the United States, cases 
 having developed recently which, as the attendant circumstances show, 
 must have resulted from infection in this country. 
 
 PRESENCE OF GID IN THE UNITED STATES. 
 
 A number of native sheep died at Bozeman, Mont., in Januarj-, 
 1904, with the characteristic symptoms of gid. These sheep were 
 brought to the notice of officials of the Montana Agricultural 
 College. On postmortem examination, bladderworms were found 
 in the brain, and through the courtesy of Professor Cooley two 
 specimens (B. A. I. Collection, No. .3644, figs. 3, 4) have been placed 
 at the disposal of this laboi'atory. These specimens agree in all essen- 
 tials with the European Ooenurus cerebralu^ so far as may be deter- 
 mined from published descriptions of the latter, no specimens for 
 comparison being at present available. The salient characteristics of 
 the American form are as follows: Each specimen is nearl}- spherical, 
 with a diameter of about 2.5 nmi. (about 1 inch). There are no sec- 
 ondary or daughter bladders, either internally or externall}. The 
 wall of the bladder consists of a thin semitransparent membrane, and 
 its surface is marked by several groups of little white spots, the 
 invaginated heads, or scolices, of the larval tapeworms, which num- 
 ber over a hundred in each specimen. Each head is supplied with a 
 double crown of 30 to 3:^ hooks, of two sizes, arranged alternately 
 (figs. 3, 4). The larger hooks measure 160 to 170/< (y^g to y|o inch), 
 and the smaller hooks 114 to 130/^ (^^^ to ylg inch) in length. In the 
 latter the ventral root is slightly bifid. 
 
 Although at present the gid parasite may be causing but little dam- 
 age in the United States, the fact should be remembered that its history 
 in other countries has shown it to be one of the most dangerous para- 
 sites to Avhich sheep are subject, and the possibilit}' kept in view that 
 it ma}' in the future become more widespread and prevalent in this 
 countr}', and that, in this event, serious losses are liable to occur. 
 Stock raisers, veterinarians, and all persons interested in live stock, 
 especially sheep, should therefore be on their guard against the gid 
 parasite, and, by taking proper preventive precautions — to be dis- 
 cussed later — avoid in this country a possible repetition of the disas- 
 trous experience of stock raisers abroad. 
 
 HISTOKICAL REVIEW OF GID. 
 
 Gid has been known for nearly three hundred years, and possibly 
 longer, it having been traced in literature as far back as 1634. 
 In that year a European surgeon named iieutten observed a sheep 
 
THE GID PARASITE IN AMERICAN SHEEP. 9 
 
 affected with vertigo, and another surgeon, Scultetus, on making a 
 postmortem examination of the animal, discovered in the brain a 
 vesicle tilled with a limpid fluid. After this date the disease and the 
 vesicle in the brain with which it is associated were noted b}' various 
 authors, who attempted to explain in various ways the cause of the 
 disease and advanced numerous theories to account for the presence 
 of the vesicle. Methods of operation for the removal of the vesicle 
 were also described, but not until the latter part of the eighteenth 
 centur}'^ was the true njiture of the water}' vesicle in the brain of 
 "giddy" sheep and cattle pointed out. In 1780 Leske demonstrated 
 the animal nature of the vesicle by the discovery of tapeworm heads 
 attached to its surface. Many years later another step was accom- 
 plished in solving the question of the etiology of gid when Siebold 
 (1852) discovered that if the gid bladderworm is fed to a dog it devel- 
 ops into mature tapeworms in the intestines of the latter. The fol- 
 lowing 3'ear Kiichenmeister (1853) showed further that the eggs from 
 tapeworms thus produced in dogs, when fed to sheep, develop into 
 bladderworms in the brain. Since that time the experiments of Sie- 
 bold and Kiichenmeister have been many times repeated, and the 
 relation between Coenurus cerebralis in the brain of sheep and other 
 animals and Taenia coenurus in the intestines of dogs, as larval and 
 adult stages, respectively, in the life history of a single species of para- 
 site, has been most firmly established. 
 
 ECONOMIC IMPORTANCE OF GID. 
 
 Gid was soon recognized in Europe, after its first discover}^ as one 
 of the most important diseases of sheep; large numbers of animals 
 were lost annually from this cause, and at times in some localities the 
 flocks were almost annihilated. 
 
 The following quotations from the literature on the subject will 
 serve to indicate the important nature of the disease, and will give 
 some idea of the damage which has been caused by the gid parasite in 
 countries w here it has been prevalent. It will be noticed that most of 
 the authors quoted refer to conditions which existed before the life 
 history of the parasite was known and before the proper means for 
 its prevention were recognized. The percentages given will, in gen- 
 eral, probably not apply at the present time, as many stock raisers of 
 Europe have long since realized the practical value of preventive 
 measures, and this has resulted in a material reduction of the general 
 mortality from gid, although in isolated cases where proper precau- 
 tions are neglected the former high percentage of mortality is still the 
 rule. 
 
 Wepfer (about 1659) reported an epizootic of the disease which 
 occurred in the year 1650 among cattle in a certain locality of Ger- 
 man}'. In 1752 there were great losses from gid among both sheep 
 11896— No. 66—05 2 
 
10 BUREAU OF ANIMAL INDUSTRY. 
 
 and cattle in Iceland, Sooner or later the disease attracted attention 
 in almost every country in Europe. 
 
 Tessier (? 1810), according- to Numan (1850), placed the annual loss of 
 sheep from gid in France at about 5 percent. Kuers (1810) estimated 
 the loss in Germany at about the same figure, and Fricke (1811) stated 
 that in his own flocks the losses at one time reached as high as 10 per 
 (Cent. Numan (1850) states that, while the disease is well known in 
 Holland, it is not so common as in some other countries, although at 
 times it assumes the character of an epizootic. He further states that 
 in some parts of Germany and Austria the loss is 10 per cent, and that 
 in many localities the sheep industry has declined serioush' in con- 
 sequence. 
 
 Fleming (in Neumann, 1892) quotes a statement of Youatt that in 
 France 1,000,000 sheep die annually from gid, and states that Gasparin 
 has put the losses in Germany at 15 per 1,000 in the first year of life, 
 5 in the second year, 2 in the third 3'ear, and 1 in the fourth. In 
 
 England, where the disease is more or less 
 prevalent, the number of sheep lost in some 
 flocks has reached as high as 35 per cent 
 (Veterinarian, 1871, p. 547). 
 
 Armatage (1895) estimates the annual losses 
 in Great Britain at about 10 per cent, and 
 states that gid "always prevails in some dis- 
 tricts, particularly in Scotland, and upon all 
 uninclosed lands where sheep are gathered 
 Fig. 1— Gid biadderworm [Coenu- in large flocks and attended by dogs." 
 rus cereb,-aus), showing the ^^ ^^ illustration of the extent to which 
 
 heads, each one of which repre- 
 sents an immature tapeworm, a single flock ma}'^ be invaded bv gid, an 
 
 m6T2Tf^s.mT ""''"'''' instance observed by Brunet (1875) in the 
 
 Bas Berry region, France, may be referred 
 to. In this case over 80 sheep in a flock of 212, or about 10 per cent, 
 were affected. 
 
 DESCRIPTION OF THE GID BLADDERWORM (COENURUS CEREBRALIS). 
 
 (Figs. 1-4, 10-12.) 
 
 Coenurus cerehmlis, the larval stage of the gid parasite, is most fre- 
 quent!}^ found in the brain of sheep and more rarely in the spinal cord. 
 It has also been found in other herbivorous animals — ox, goat, reindeer, 
 roedeer, antelope, dromedary, and horse. No authentic case of C'a'nu- 
 7nis cerebralis in man has been recorded. A number of isolated cases 
 are on record in which bladderworms VQi^emhWng Ovnu rus certhralis, 
 and probably identical with it, have been found in locations other 
 than the brain. Eichler and Nathusius have reported such bladder- 
 worms in the subcutaneous tis.sue of sheep, and Heincke (1882) has 
 
THE GID PARASITE IN AMERICAN SHEEP. 
 
 11 
 
 rocorded the present'e of a ODnirus in the C3'e of ii horse. Kabe (1889) 
 discovered in the brain, muscles, lymphatic glands, and thyroid body 
 
 >4 
 
 Fig. 2. — Diagrammatic section of a gid bladderworm {Ccenurus ccnbraiis): a. normal disposition of 
 scolcx; b, c, d, c, diagrammatic representation to show the homol >gy between cysticercus and 
 coenunis. (After Railliet, 1886, p. 243, fig. 134.) 
 
 of an antelope specimens of a bladderworm which he identified as 
 Canurus cerehralis. In general, however, C<jenurus cerebralis fails to 
 develop in an}^ other location 
 than the central nervous sys- 
 tem, and the embr3'os which 
 do not succeed in reaching 
 the brain or spinal cord soon 
 degenerate. 
 
 The bladderworm (figs. 1, 2) 
 consists of a membranous 
 vesicle, the wall of which 
 bears numerous small invagi- 
 nations resembling tapeworm 
 heads (fig. 3), each one of 
 which, when swallowed b}^ a 
 dog, is capable of transform- 
 ing into an adult tapeworm, 
 Taenia cmua'us. In its growth 
 the vesicle tends to assume a 
 spherical form and attains a 
 size varying from that of a 
 hazelnut to that of a hen's 
 eg^. The form of the bladder 
 is modified according to its location 
 canal it becomes much elongated. 
 
 Fig. 3.— Larval tapeworm head dissected away from 
 the wall of a gid bladderworm (Ccenurus cerebralis). 
 X 38. (Original drawing, specimen No. 3644, B. A. I. 
 Helminthological Collection.) 
 
 When situated in the spinal 
 The wall of the bladder is very 
 
12 
 
 BUREAU OF ANIMAL INDUSTRY. 
 
 thin, translucid, and contains contractile fibers. It is filled with a 
 colorless, watery fluid containing- 1 to 2 per cent of animal matter 
 and less than 1 per cent of inorganic salts. The heads of the larval 
 tapeworms, which appear as little white spots arranged in irregular 
 groups and usually confined to one region of the vesicle, probably cor- 
 responding to the posterior part of the eniibryo, may number more 
 than 500 in a single specimen, but usually they are not so numerous. 
 They are general]}' found invaginated and project into the interior of 
 the vesicle; but Davaine (1858) has observed that the}- are capable of 
 
 evagination, and thus become an active source of 
 
 irritation to the brain. Not all 
 
 of the heads are found equally 
 
 developed. Some of them can 
 
 not ])e distinguished from the 
 
 head of the adult, while others 
 
 are rudimentar3\ 
 
 The hooks, suckers, and other 
 
 details of the head are similar 
 
 in the larva and in the adult, 
 
 and will be described in con- 
 nection with the description of 
 
 the latter. 
 
 DESCRIPTION OF THE GID TAPE- 
 WORM (t^nia ccenurus). 
 
 ( Figs. 6-8, see also figs. 3-5, 9. ) 
 
 Tsenia ccenurus^ the adult 
 
 stage of the gid parasite, is 
 
 found in the intestines of dogs, 
 
 and is said to occur also in foxes, 
 
 and probably also in wolves. 
 
 It is not known to occur in other animals. Another 
 
 tapeworm of the dog, Tsenia seivalts^ is often mistaken for it. 
 
 pare figs. 4, 5, 8 6; 9.) 
 
 Omitting an extensive discussion of the anatomy of the worm, the 
 essential characteristics of Tsenia cmnurus are as follows: 
 
 The average length is 10 to 60 cm. (16 to 21 inches) and the maxi- 
 mum 1 meter (10 inches). It possesses a head, or scolex, an unseg- 
 mented neck, and a long segmented portion consisting of two hun- 
 dred to two hundred and fifty segments, or proglottids (fig. 6). 
 
 The fully developed head is pyriform and measures about 0.8 mm. 
 (aV inch) in diameter. It is supplied with four suckers, 0.30 mm. 
 (sV inch) in diameter, and a rostellum, also about 0.30 mm. in diame- 
 ter, bearing a double crown of 22 to 32 hooks (fig. 1) of two kinds, 
 large and small, arranged alternately. The suckers and rostellum 
 
 Fig. 4. — Hooks from the 
 gid bladderworm (Cte- 
 nurus cerebraUs) . X 240. 
 (Original drawing, 
 specimen No. 3644, B. 
 A. I. Helminthological 
 Collection.) 
 
 Fig. 5.— Hooks from a 
 bladderworm of the 
 rabbit ( Qvnums serialis, 
 the larval stage of a 
 tapeworm of the dog, 
 Tienia serialis). X 240. 
 (Original drawing,spec- 
 imeu No". 1823, B. A. I. 
 Helminthological Col- 
 lection.) 
 
 (Com- 
 
THE GID PARASITE IN AMERICAN SHEEP. 
 
 13 
 
 serve to attach the worm to the intestinal wall of its host. The large 
 hooks measure 150 to ITOyu (j^j to -^^^ inch) and the small hooks 90 
 to 130yw (^io to yis inch) in length. 
 
 The neck is slender and 2 to 3 mm. (jV to ^ inch) long. In the region 
 of the neck the segments (tig. 6) are very short and narrow, but 
 toward the posterior end of the worm 
 they gradually increase in size. The 
 last twelve to fifteen segments are 
 much longer than broad, in form 
 somewhat resembling cucumber 
 seeds, and measure 8 to 9 mm. (about 
 I inch) long by 3 to 5 mm. (i to | 
 inch) broad. Near the middle of the 
 right or left lateral margin of each 
 segment is a small opening — the 
 genital pore. 
 
 During the life of the worm new 
 
 Fig. 6.— Portions of an adult gid tapeworm 
 [Tmnia coeiiurus). Natural size. (After 
 Railliet, 1893, fig. 146, p. 2.i2.) 
 
 segments are continuallv being 
 
 added in the neck region liy a 
 
 process of intercalation. The 
 
 FIG. 7.-^exuaiiy mature segment of the gid tape- Segments when first formed are 
 
 worm ( Txnia ccenurus) showing: cjh cirrus pouch; gmall and SCXUall V Undeveloped. 
 
 jrp,genital pore; 71, nerve; o!', ovary; Si?, shell gland; /^ i 1 1 i "^ .i 
 
 <, testicles; <r, transverse canal; «^ uterus; )', vagina; LrraClUally, nO\\ e^ Cr, tUey are 
 
 vc, ventral canal; vd, vas deferens; vg, yolk gland, pushed backward b V Still 
 
 X 20. (After DefEke, 1891, pi. 1, fig. 3.) '■ ^ i • i * i i 
 
 younger .segments which develop 
 in front of them. They grow larger in all dimensions, and the 
 sexual organs dev^elop (fig. T), reach maturity, and produce eggs, 
 which are stored up by thousands in the uterus of each segment. 
 Finally the gravid segments break away from the end of the chain and 
 pass out of the dog's intestine. It results from this manner of growth 
 that the small segments farthest anterior are the youngest, and the 
 
14 
 
 BUREAU OF ANIMAL INDUSTRY. 
 
 large hindermost segments are the oldest; thus, in a single worm, seg- 
 ments in all stages of development may be found. 
 
 The most conspicuous structure in the posterior segments (tig. 8 C) 
 is the uterus tilled with yellowish or brownish eggs. The gravid 
 uterus has a median stem with eighteen to twenty-six lateral branches 
 
 Fig. 8. — Gravid segments of tapeworms of dogs, showing the median stem of the uterus and Its lateral 
 branches. (A) Txnia serrata, X 4; {B) T. manjinata, X 6; (C) T. coenurus, X 10-15. (After Leuckart, 
 1880, p. 720, fig. 308.) 
 
 on each side. The latter are almost parallel to each other, and are 
 unbranched or only slightly branched. 
 
 The eggs, found in the gravid uterus, contain embryos with six 
 hooks and measure from 31 to 36 yw (about ^^^o^ inch) in diameter. 
 
 LIFE HISTORY OF THE GID PARASITE. 
 
 As already stated, the gid bladderworm, Ctemirus cerebralis^ and 
 the tapeworm, Tsenia coenurus^ are intimately related, the former 
 being the larval stage of the latter. 
 
 In detail the life history is as follows: A dog infected with Taenia 
 canurus scatters the eggs and gravid segments of the tapeworm over 
 the ground. Those eggs which fall into moist places may live for 
 several weeks, but those exposed to hot, dry weather preserve their 
 vitality only a few days at most. Sheep and cattle while grazing or 
 drinking are liable to swallow some of the eggs thus spread broadcast 
 by the infested dog. By the action of the digestive juices the shells 
 of the eggs are dissolved and the embrj^os contained set free. The 
 embryos then bore out of the intestine by means of their hooks and 
 wander among the tissues. This migration is undoubtedly aided by 
 the blood current in vessels penetrated by the embryos, which are 
 thus carried passively to various parts of the body. Normally only 
 those embryos which reach the central nervous sj'stem continue their 
 development. Others failing to reach this location may live for a 
 while, but generally die and soon disappear. After reaching the 
 
THE OID PARASITE IN AMERICAN SHEEP. 
 
 15 
 
 brain or spinal cord, which may occur within eight days after infection, 
 the embryo loses its hooks and transforms into a small cyst. The 
 3^oung ccBnurus preserves its power of locomotion for some time and 
 may burrow along the surface of the 
 brain, leaving a shallow, sinuous furrow 
 (fig. 10) in its wake, but within a few 
 days it becomes stationary. These furrows 
 are to be found fourteen to thirty-eight 
 davs after infestation; near the termi- 
 nation of each is a small vesicle, the young 
 gid bladderworm. As determined exper- 
 imentally by Baillet, the vesicle, two or 
 three wrecks after infestation, has attained 
 a diameter varving from 0.6 to 3 mm. (jV 
 to ^ inch); on the twenty-fourth day it is 
 as large as a pea, but the w^all still re- 
 mains thin and transparent. The heads 
 begin to appear by the thirty-eighth day, 
 when the vesicle has reached the size of 
 a cherry, but they do not seem to attain 
 their full development before the end of 
 two or three months. The vesicle, how- 
 ever, continues to grow, and new heads 
 are in continuous process of formation, 
 so that in addition to fully formed heads, 
 very rudimentary heads and intermediate 
 stages between the two are likely to be 
 found on the surface of the same bladder. 
 
 When a brain containing a bladderworm is eaten by a dog, the wall 
 of the vesicle is digested, but the heads remain uninjured by the 
 digestive juices and attach themselves to the wall of the intestine and 
 
 Fig. 9— Gravid "egment of Taenia seri- 
 alis, a tapeworm of dogs often con- 
 fused with T.ctt'/iin-KS. X14. (Original 
 drawing, specimen No. 2839, B. A. I. 
 Helminthologieal Collection.) 
 
 Fig. 10. — Brain of lamb showing the furrows produced by the migration of young gid bladderworms, 
 taken at a time immediately following the period of invasion— i. e., from fourteen to thirty-eight 
 days after infestation. Natural size. (After Leuckart, 1879, fig. 81, p. 173.) 
 
 develop into the adult tapeworm. In one to two months the posterior 
 segments of the worm become gravid with eggs, and breaking away 
 from the rest of the chain begin to pass from the dog's intestine. 
 
16 BUREAU OF ANIMAL INDUSTRY. 
 
 SUSCEPTIBILITY OF SHEEP AND OTHER ANIMALS. 
 
 Gid is exceptional in sheep over two years old, the great majorit}^ 
 of animals "which present symptoms of the disease being lambs and 
 yearlings. The disease is more rare among cattle and goats, and still 
 more rare in other animals. Cattle seem to be susceptible for a 
 longer period than sheep, and although gid is more frequent in calves 
 and yearlings, animals as old as five or six years are still subject to 
 infestation. 
 
 Certain breeds of sheep seem to be more susceptible than others, 
 and in some cases this has been explained by the fact that some breeds 
 graze closer to the ground and thus are more liable to take in tape- 
 worm eggs and segments than others. The greater susceptibility of 
 young animals has not been fully explained, but it has been supposed 
 that the embrj^os of the worm are unable to penetrate the tinner 
 tissues of adult animals, and consecpiently do not reach the brain. 
 
 SYMPTOMS. 
 
 The following account of the s3^mptoms of gid is based mainly on 
 the description of the disease in sheep, given by Neumann (1892). 
 The symptoms in cattle and other animals are of the same general 
 character as those in sheep, showing minor ditferences probably in 
 correspondence with the different natures of the animals affected. The 
 t3'pe of S3"mptoms varies according as the bladder worm is located in 
 the brain or spinal cord. If the parasite is located in the brain it 
 gives rise to cephalic gid; if in the spinal canal, to raechillary gid. 
 
 Ceijludlc gid.- — Unless the infestation is very heavy no symptoms are 
 likel}" to appear during the stage of invasion of the parasites, or they 
 ma}' be slight and pass unnoticed. When early symptoms occur the}' 
 appear generally in the second or third week following infestation. The 
 affected animal shows signs of congestion of the brain, there is indif- 
 ference and weakness, the head is of unusually high temperature and 
 is held in an abnormal position, and the eyes arc inflamed. Peculiar 
 actions ma}' become evident. 
 
 Frequently the animal turns in circles, or wheels about in one spot 
 as on a pivot. In some cases it staggers about as though intoxicated, 
 stumbles, and often falls. The eyes are turned in or out, there is 
 grinding of the teeth, and sometimes convulsions. The animals may 
 die in a few days in severe cases, but generally the symptoms disap- 
 pear in eight or ten days, and a period of apparent recovery follows, 
 corresponding to the period of growth of the parasite. In about 2 per 
 cent of animals attacked the parasites apparently die, as no later symp- 
 toms develop, but in the vast majority of cases, at the end of four to 
 «ix months, symptoms appear which mark the final stage of the dis- 
 ease, leading almost invariably to a fatal termination within a few 
 
THE GID PARASITE IN AMERICAN SHEEP. 17 
 
 weeks at most. Usually these symptoms are the first to be noticed, as 
 the initial symptoms are generally so slight that they pass nniveog- 
 nizecl. Prior to the onset of the tinal symptoms and during- the growth 
 of the parasite certain slight signs of an abnormal condition of the 
 brain will be noticed from time to time by the careful observer, espe- 
 cially in stormy weather. The time at which the symptoms of the 
 tinal stage of the disease appear varies somewhat and according to the 
 time at which infestation occurred, but it is generallv toward the end of 
 winter or in the spring. The symptoms at this stage may be consid- 
 ered as due in part to the pressure of the cfjenurus bladder on the 
 brain, and in part to the active irritation produced by the larval tape- 
 worm heads which are capable of being thrust out from the surface 
 of the bladder. The symptoms vary according to the region of the 
 brain occupied by the parasite. 
 
 Generally, however, the affected sheep holds his head in an unusual 
 position, his eyes are fixed, with dilated pupils, and he pushes against 
 obstructions. He becomes feeble, loses his appetite, and lags behind 
 the flock. He moves in circles which gradually become smaller and 
 smaller until he turns as on a pivot, and he usually turns toward the 
 side on which the brain is compressed. If the parasite is located in 
 the anterior part of the brain, the sheep is likely to move straight 
 forward, holding his head down and lifting his feet high. A great 
 variety of other movements ma}^ be executed, the type of movements 
 depending upon the locality of the brain affected. A characteristic 
 of all these peculiar actions is their automatic and intermittent nature. 
 They recur several times during the day, and ma}^ continue to apjjear 
 during a period of four to six weeks, at the end of which the animal 
 dies from paral^ysis or exhaustion. 
 
 Medullary gid. — When the gid parasite is located in the spinal cord 
 it generally occurs in the lumbar region, and the disease is then termed 
 lumbar gid, or hydatic paraplegia. 
 
 The chief symptom of lumbar gid is the gradually increasing weak- 
 ness and paralysis of the hind quarters. The bladder and rectum 
 become paralyzed, the wool is shed, and the animal becomes progres- 
 sively thirmer, although he may retain his appetite and eat enormousl}^ 
 This condition may persist for several months before death occurs 
 from general debility and exhaustion. 
 
 PATHOLOGY. 
 
 (Figs. 10-12.) 
 
 Neumann (1892) gives the following account of pathological lesions 
 occurring in gid: 
 
 Pathological anatomy. — At the autopsy of animals which have died of gid one or 
 more Coenures are found in the cranium, as much more developed as the disease has 
 been prolonged. When speaking of its etiology, and of the experiments which have 
 
18 
 
 BUREAU OF ANIMAL INDUSTRY 
 
 established this, the developmental phases of the parasitic vesicle were described. 
 In practice, the number of Ccenures is generally limited, though Huzard has counted 
 more than thirty in the head of a land). Their size and development are generally 
 in inverse proportion to their number. Huzard has seen some which occupied nearly 
 one-half of the cranial cavity. 
 
 These vesicles are found at various parts of the brain. When they are small and 
 deeply situated they are surrounded l)y a pseudopurulent exudate, which is yellow 
 and creamy in places. If the Coenurus is voluminous the brain substance in its 
 
 Fig. 11. — Skull of a sheep shoving the brain infested with a gid bladderworm {Ccenurus rnrhra/i-i), 
 two-thirds natural size, (.\fter Railliet, 1886, p. 244, tig. 135.) 
 
 vicinity is depressed, atrophied, wasted, and forms a more or less regular pouch, the 
 wall of which is formed of flexuous, interrupted, or l)roken nerve tubes that are less 
 numerous than in the normal substance; by nerve cells which are no longer in com- 
 munication with the nerve tubes; by a large quantity of amorphous substance and 
 molecular granules; and lastly, by calcareous crystalline particles. Capillary vessels 
 traverse this layer, and are continuous with those of the cerebral substance ( Robin, 
 quoted by Reynal). This pouch contains a grumous purulent matter, and the 
 peripheral cerebral substance is inflamed, dense, and granular. 
 
THE GID PARASITE IN AMERICAN SHEEP 
 
 19 
 
 When the Ctenurus is in a ventricle, the roof of this is thinned and sometimes 
 reduced to its envelopes; the septum lucidum, posterior pillar of the fornix and the 
 corpus callosum are also thinned, and even perforated, and pushed toward the hemi- 
 sphere or into the opposite ventricle, into which the vesicle sometimes protruih's. 
 
 The old and voluminous Cd-nures, situated on the superficial parts of the l)rain, 
 have, by compression, caused absorption and attenuation of the roof of the cranium, 
 which yields to pressure of the fingers (fig. 12). 
 
 In medullary gid the Ctenurus is elongated, fusiform, and from 3 to 5 cm., and 
 even a foot long (Numan) . Usually there is only one and it is lodged in the lumbar 
 region;, it may, however, occupy the cervical region (May), or the posterior j)art of 
 the medulla oblongata (St()ring). In some cases it has undergone calcareous degen- 
 eration and is only recognizable by its hooks, which have persisted ( Roll ). It some- 
 times only occupies oiie-half of the spinal cord, sometimes the two divisions, or it is 
 
 Fig. 12.— Sheep'3 skull, showing perforations resulting from the presence of gid bladderwornis. 
 (After Dewitz, 1892, p. 65, fig. 47.) 
 
 intermediate, and completely separates them ( Yvart). It may be situated deeply or 
 only l^e beneath the arachnoid. The medullary substance is atrophied and hyper- 
 emic where it is located or it is softened. The muscles of the hind quarters are 
 wasted and otherwise show the alterations of cachexia. 
 
 In a large numberof animals there are found in various organs — and especially the 
 heart, lungs, liver, spleen, mesentery, and muscles — some round or ovoid greenish 
 corpuscles from 1 mm. to 4 mm. in diameter. They are composed of an enveloping 
 membrane and granular contents rich in fat globules. These are atrophied and 
 degenerated Cu-nures, the remains of erratic embryos which have not met with the 
 conditions favoral)le for their development. Nathusius and p]ichler have seen some- 
 what large Co-nures in the subcutaneous connective tissue of the calf and sheep. 
 
 The malady having generally a chronic course there are observed more or less 
 everywhere the lesions of pronounced cachexia. 
 
20 BUREAU OF ANIMAL INDUSTRY. 
 
 DIAGNOSIS. 
 
 In diagnosing gid care should be taken not to confuse it with vertigo 
 due to heat, epilepsy, blindness, false gid due to grul)s in the nasal 
 cavities, and inflammation of the intracranial sinuses. Likewise, 
 medullary gid should not be confounded with the trembling disease 
 (Scotch louping-ill) or lumbar prurigo. 
 
 In some respects the symptoms of gid present many similarities to 
 those of the so-called loco disease of the Western States, and it does 
 not seem unlikely that in some cases the two diseases have been con- 
 fused. The latter disease, however, is more chronic in its course and 
 does not present the acute symptoms of gid. It is also likely to 
 become evident in animals too young to allow of sufiicient time for 
 the development of symptoms of gid, except in cases where early symp- 
 toms occur corresponding to the stage of invasion of the parasite. 
 Loco disease, moreover, rarely seems to be a direct cause of death, and 
 the condition of "loco" when once established persists indefinitely. 
 
 When gid is suspected in a flock the be^t means for a positive diag- 
 nosis consists in killing one of the aflected animals and examining the 
 brain and spinal canal for the presence of the bladderworm. 
 
 TRKATMENT. 
 
 Treatment of gid with drugs is useless, and, on account of the loca- 
 tion of the parasite, the various methods of operation which have been 
 practiced are also of little practical use. Trephining and removing 
 the parasite, cauterizing, several days refrigeration of the cranium 
 wuth ice, or continuous irrigation of the skull with cold water for a 
 period of two weeks, has resulted in a cure in some cases. An oper- 
 ation may be attempted in the case of an especially valuable animal, 
 but in general the surest econom}' is the slaughter of the animals as 
 soon as sj'mptoms become evident. In case the disease is recognized 
 during the period of invasion the animals may be fattened and killed 
 ])efore the flnal stage of the disease begins or immediately upon the 
 appearance of the final symptoms. 
 
 PREVENTION. 
 
 Prevention of gid is, comparative!}^ speaking, a simple matter. With 
 our complete knowledge of the life history- of the gid parasite, it is 
 possible to prescribe certain rules which, if observed, will efli'ectually 
 prevent the occurrence and spread of the disease. 
 
 All superfluous dogs should be killed. It is hardly necessar}' to 
 insist upon the destruction of wolves and foxes, on account of the 
 possibility of infestation from this source, since they are alread}^ suffi- 
 cientl}" under the ban for other reasons. A certain number of dogs 
 are, of course, indispensable, and these animals should be treated sys- 
 
THE GID PARASITE IN AMERICAN SHEEP. 21 
 
 tematictilly iit intervals for tapewoniLs. While the dog- is underuoiiro- 
 treatment he should be kept tied up and all feces collected and l)urned 
 or buried in quicklime. Prior to the administration of the vermifuge, 
 a laxative, such as castor oil, should be given to empty the ))owels, and 
 the animal then starved or fed on milk or soup until the following day. 
 
 In giving fluid medicine to a dog the cheek should be pulled away 
 from the teeth at the angle of the mouth, the medicine poured into 
 the pouch thus formed, and the dog's head held until he swallows the 
 dose. If the animal is refractory a cord thrown in two half-hitches 
 oVer his nose will be of assistance in holding him. After the adminis- 
 tration of the dose the dog should be tied short enough to prevent his 
 lowering his head and getting rid of the medicine by vomiting. 
 
 Preliminary treatment with a laxative not only serves to clear out the 
 intestines so that the vermifuge will act more vigorously, })ut usuallv 
 also expels fragments of tapeworms, from the number of which some 
 idea of the degree of infection may be gained. An experienced 
 observer will also be able to determine by stud}- of these fragments 
 (tigs. 8, 9) the species of tapeworms to which they belong. Whether 
 segments appear in the dog's feces or not, the practice of occasional 
 vermifugal treatment should not be neglected. To render more cer- 
 tain the expulsion of all tapeworms the treatment may be repeated in 
 two weeks or a month. 
 
 The following notes on vermifuges and their administration are taken 
 from Stiles (1898): 
 
 In selecting a remedy it is well to consider the following drugs. The doses (apothe- 
 caries' weight) here given and the remarks on the drugs are abstracted from Frendi 
 (1896). 
 
 The doses of pelletierine tannate are, for adults, 5 to 15 grains; jjuj^pies, one-half 
 to 5 grains. Pelletierine is undoubtedly the most efficient and innocuous ta?niaciile 
 for the dog we possess, but is not much used on account of its expense. French has 
 frequently found it most useful when the stomach has refused to retain other reme- 
 dies. It should be administered in gelatin-capsular form in conjunction with pow- 
 dered purgatives. 
 
 Aspidium is perhaps the most reliable of all the vermifuges with the exception of 
 pelletierine. For everyday practice it is to be preferred to all other remedies when 
 given in the form of oleoresin. Doses: For adults, 15 to 40 minims; puppies, 5 to 15 
 minims. The dose of the liquid extract is the same. 
 
 Kamala is a very efficient ta^niacide with drastic purgative properties. Given in 
 small amount as an adjunct to other tn^niacides, particularly to the oleoresin of male 
 fern, it will be found a very valua)>le remedy. Doses: Adults, 15 to .SO grains; pup- 
 pies, 3 to 15 grains. 
 
 Brayera (U. S. P.), Cusso (B. P.), yields kosin or koussin, to which it owes its 
 ticniacidal properties. It is one of the best and safest t;cniacides, its action being 
 directly toxic to the worm, but it is too expensive for ordinary practice. The infu- 
 sion {Iiifusuin brayera', U. S. P.) and fluid extract {Extraduyn hrayene fluidum) are 
 both too bulky and disagreeable for administration to dogs. Kosin may be given in 
 capsules in doses — adults, 10 to 40 grains; puppies, 10 to 20 grains. The drug usually 
 acts as its own cathartic, but it is better to employ some adjunct for this i>urpose. 
 
 Powdered «reca }(«/, when freshly ground, is a very good remedy for tapeworm. 
 
22 BUREAU OF ANIMAL INDUSTRY. 
 
 When old, it will generally be found inert; consequently, it is best always to pur- 
 chase the nut and grind or grate on an ordinary nutmeg grater. It is still largely 
 used by British veterinarians and is a favorite with some Americans, but it can not be 
 regarded as being either as effectual or easy of administration as the two preceding 
 drugs. Its effects on puppies are not unattended with danger, on account of its great 
 astringency; but with due regard to subsequent purgation it is a perfectly safe 
 reniedy. Mayhew's method of prescribing 1 to 2 grains to every pound weight of 
 the dog is usually followed, but the smaller quantity will generally suffice, provided 
 the powder is freshly ground. It may be conveniently given in gelatin capsules, 
 accompanied or followed by a purgative. 
 
 Turpentine is a powerful remedy against tajieworms, l)ut it is regarded as being 
 somewhat dangerous from its liability to j)roduce strangury and renal inflammation. 
 These effects are said to be less pronounced after large than after small doses, but 
 large doses are more liable to cause gastric and enteric inflammations. It can hardly, 
 therefore, rank with the best remedies. Administer in emulsion with white of an 
 egg, mucilage, milk, or oil. Doses: Adults 10 to 15 minims; puppies, 3 to 10 minims. 
 
 Doctor Hoskins has had very satisfactory results with this drug in puppies under 
 6 months of age and has never noticed any gastric or renal results. In very young 
 puppies he rarely gives over 2 minims, carrying it up to 10 minims and repeating for 
 two or three days on an empty stomach in the morning, allowing no food for an 
 hour or two after its administration. 
 
 The following- .sug-gestions as to doses, compiled from various sources, 
 are taken from Curtice (1S90): 
 
 (1) Allow 2 grains of freshly powdered areca nut for each pound of the dog's 
 weight; administer dose in soup or milk, stirring it well, or by mixing it in butter 
 or molasses. Follow in two hours with a tablespoonful of castor oil for a moderate- 
 sized dog, giving the oil alone or in three times its quantity of milk. 
 
 Ziirn advises 4 drams of areca nut for a large d(ig, 2h drams for a medium-sized 
 animal, and 1 dram for a small dog." 
 
 (2) One teaspoonful of turpentine and two tablespoonfuls of cast(jr oil given in a 
 cup of milk. The flnal dose of physic is not given in this case. 
 
 (3) Twenty drops of oil of male shield-fern, 30 drops of turpentine, and 60 drops 
 of ether. Beat together with one egg and give to the dog in soup. 
 
 (4) Hagen advises 80 grains of oxide of copper with 40 grains each of powdered 
 chalk and Armenian bolus. Mix with sufficient water to make an adherent mass 
 and divide into 100 pills. Administer one pill three times daily for ten days, in meat 
 or butter. 
 
 (5) Roll prescribes the following dose for large dogs; smaller doses should be given 
 in proportion to the size of the dog: 
 
 {<() Two drams each of extract of male fern and of powdered male fern; or 
 
 (b) Decoction of 2^ ounces of pomegranate-root bark in water, reduced to 6 fluid 
 ounces, to which add 1 dram of extract of male fern. Give in two doses, at intervals 
 of one hour; or 
 
 (c) One-half to 1 ounce of kousso, made into pills, with honey or molasses and a 
 little meal; or 
 
 (f?) From li ti) 2-2 drams of kamala, stirred with honey or water, and given in two 
 doses inside of an hour. 
 
 [«, b, and c should be followed in two hours with castor oil, but this is not neces- 
 sary for d.] 
 
 " The doses given by Ziirn are two to three times larger than those prescribed by 
 American authorities iov freshly powdered areca nut, and should be used cautiously. 
 
THE (ilD PARASITE IN AMERICAN SHEEP. 23 
 
 In jidclition to treating dog-s with vermifuges to rid tliem of the 
 gid tapeworm, and tim.s removing the source from wdiich .sheep and 
 cattle become infested, it is also essential that precautions be taken in 
 turn to prevent the dogs from acquiring the parasite. This is accom- 
 })lished h}^ preventing dogs from eating those portions of the carcasses 
 of '"giddy" animals — namely, the brain and spinal cord — in which the 
 bladderworm is located. These poi-tions should be destroyed by burn- 
 ing, or rendered, or they may be thoroughly boiled, and can then be 
 fed with safety to the dogs. 
 
 Not onl}' is it a matter of immediate economy to slaughter animals 
 affected with gid as soon as the symptoms indicating the final stage of 
 the disease appear, and while they are still in good flesh, but it is also 
 advisable from the prophylactic standpoint in that it removes a source 
 of infestation to the dogs, and thus indirectly protects sheep and cattle 
 f roiii infestation, provided, of course, that the heads of the slaughtered 
 animals are properl}' disposed of as suggested above. 
 
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