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Issued February IG, 1914. 
 
 |S, DEPARTMENT OF AGRICULTURE, 
 ''BUREAU OF ANIMAL INDUSTRY. 
 A. D. MELVIN. Chief of BuREAr. 
 
 THE OPHTHALMIC TEST 
 FOR GLANDERS 
 
 WASHINGTON; 
 GOVERNMENT PRINTING OFFICE. 
 
 1914. 
 
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 Y ,; Issued February 16, 1914. 
 
 U. S. DEPARTMENT OF AGRICULTURE, 
 
 BUREAU OF ANIMAL INDUSTRY. 
 A. D. MELVIN, Chief of Bureau. 
 
 THE OPHTHALMIC TEST FOR GLANDERS. 
 
 During the past few years the ophthalmic maliein test 
 has gained great favor in the diagnosis of glanders. The 
 popularity of the test is rapidly gaining wherever this 
 method has been applied, and among its supporters we 
 find at the present time the best authorities on the subject 
 of glanders and on clinical diagnosis. 
 
 The Bureau of Animal Industry, in consideration of the 
 favorable results obtained from this test in other countries, 
 has for a period of more than a year carried out extensive 
 investigations with a concentrated maliein. For this 
 purpose the cooperation of official and practicing veteri- 
 narians was solicited in various parts of the country. 
 Ophthalmic maliein was furnished to all practitioners who 
 desired to make a careful study of the method and establish 
 its comparative value with other tests for glanders, espe- 
 cially the subcutaneous maliein test. In this experimental 
 work about 18,000 horses have been subjected to the 
 ophthalmic test, and in most cases it has been applied 
 simultaneously with the subcutaneous maliein test. The 
 data collected from the reports of a gi-eat number of veteri- 
 narians indicate satisfactory results from the eye test, and 
 those who employed the method appear to be unanimous 
 in their preference of the eye test over the subcutaneous 
 test. 
 
 The comparative diagnostic tests for glanders which 
 have been carried out by the Bureau of Animal Industry 
 in connection with immunization experiments in glanders, 
 and in several outbreaks of the disease, proved the eye 
 
 29686—14 
 
test to be reliable and most practicable. In most of these 
 instances the results were controlled by post-mortem 
 examinations. 
 
 As a result of these favorable findings the bureau has 
 decided to recognize this method of diagnosis for the 
 interstate shipment of equines. 
 
 This method has a great advantage over others by its very 
 simple application. It may be readily executed by any 
 veterinarian, and its other advantages are that the results 
 are obtained in a comparatively short time and are, as a 
 rule, distinct and definite. The simplicity of its applica- 
 tion is plainly manifest when compared to the subcuta- 
 neous test, as it is only necessary to drop into one of the 
 eyes of the animal to be tested 3 drops of concentrated 
 mallein or, by a still simpler procedure, to dip a camel's- 
 hair brush into mallein and introduce this into the con- 
 junctival sac of the animal. The reaction usually com- 
 mences in 5 to 6 hours after the introduction of the mallein, 
 and lasts from 24 to 36 hours. A positive reaction is mani- 
 fested by a purulent secretion from the tested eye. This 
 may be very profuse or slight, sometimes associated with 
 a severe conjunctivitis and edema of the lids and at other 
 times without any inflammatory symptoms being present. 
 At times only a very small quantity of pus may be present 
 in the inner canthus of the eye. At other times the reac- 
 tion may result in a true pyorrhea. The reaction manifests 
 itself in varying degrees in different animals, but the in- 
 tensity of the reaction has no relation to the extent of the 
 disease in the reactor. 
 
 The essential factor in obtaining satisfactory results from 
 the test appears to be in the use of the right kind of mallein. 
 It must be by all means a concentrated mallein, and appar- 
 ently the best results follow the use of raw or precipitated 
 mallein, the former representing the mallein obtained after 
 the concentration of the filtrate from the bouillon cultures 
 of the glanders bacilli. The ordinary mallein used for sub- 
 cutaneous testing is not adaptable, and the few failures 
 which have been reported in the literature were due to 
 the fact that the mallein employed was not sufficiently 
 concentrated. 
 
INSTRUCTIONS FOR APPLYING THE OPHTHAL- 
 MIC TEST. 
 
 Before the application of the ophthalmic test the animals 
 should be carefully examined to ascertain whether the 
 eye shows conjunctivitis or other changes which are asso- 
 ciated with suppuration. Should such be present, the 
 test should not ha applied. 
 
 An average reaction to the ophthalmic test. 
 
 Th9 test consists in introducing into the conjunctival 
 sac of the eye several drops of either undiluted raw mal- 
 lein or a solution of precipitated mallein (0.1 to 0.2 c. c. 
 per horse). This may be introduced either with the aid 
 of an eye dropper or preferably with a camel's-hair brush 
 
by applying the brush gently along the inner surface of 
 both the upper and lower eyelids. The other eye is not 
 treated, but servee as a control for comparison of the re- 
 action. For the tasting of horses in the same stable the 
 same dropper or camel's-hair brush may be used for all 
 animals, but the dropper or brush thould be sterilized 
 before use upon different lots of horses. 
 
 As soon as the mallein is introduced into the eye prac- 
 tically all animals show a lacrimation, increased redden- 
 ing of the conjunctiva, and slight photophobia. No sig- 
 nificance should be given to these symptoms. They 
 disappear in one or two hours. A pseudo-reaction can be 
 produced by artificial or accidental irritation of the eye. 
 
 The characteristic manifestation of the reaction for 
 glanders commences as a rule from 5 to 6 hours and lasts 
 24 to 36 hours, sometimei: longer. It consists of a purulent 
 discharge from the conjunctival sac which is typical and 
 is frequently associated with reddening, swelling, and 
 gluing of the eyelids. It is advisable to examine the 
 tested animals in a good light from 12 to 24 hours, or pref- 
 erably 16 hours, after the application of the test. 
 
 A suppurative discharge of varying quantities is con- 
 sidered a positive reaction. The conjunctiva and the eye- 
 ball should also be included in the examination after 
 examining the discharge. By removing the purulent dis- 
 charge (either by the stable attendant or by the animals 
 licking each other, etc.) the positive result may be obliter- 
 ated. In such cases dried pus may be frequently found 
 on the parts around the eye, or the exposure of the con- 
 junctiva by means of pressure by the thumb and finger 
 will show fresh, purulent material. 
 
 Generally the positive ophthalmic reactions are not 
 accompanied by fever or systemic disturbances. Occa- 
 sionally, however, affected horses are hypersensitive to 
 such a degree that even the few drops of mallein placed in 
 the eye may enter the circulation and produce fever. 
 Therefore, it is advisable, when possible, to accompany the 
 ophthalmic reaction with temperature readings. For this 
 purpose the temperature should be taken twice, the first 
 time when the eye test is being made, and the second time 
 
when it is judged. In a doubtful eye reaction where there 
 is an increased temperature of 1^° F., the test should be 
 considered positive if the animal had a normal tempera- 
 ture at the time the test was made. 
 
 In the absence of any secretion the test should be con- 
 sidered negative. When there is a mucous secretion or 
 lacrimation during the period of reaction the test must be 
 considered as atypical, and in such cases it may be 
 repeated the same day, when as a rule the results are more 
 confirming. 
 
 The application of the ophthalmic test should not be 
 repeated more than three times on the same animal within 
 a short period, as experiments show that the reaction after 
 the third application made within three months usually 
 loses its intensity in positive cases and on subsequent 
 tests may be entirely absent. In cases where the results 
 of the second test immediately following the first test are 
 atypical, the blood of such animals may be drawn and 
 forwarded to a laboratory for the serum diagnosis, as the 
 instillation of ophthalmic mallein does not influence this 
 method of diagnosis. From experience gained with the 
 eye test such a procedure would become necessary only in 
 a comparatively few cases. In the control of glanders, 
 animals may be retested every six months with satisfactory 
 results. 
 
 The mallein for the eye test is a clear, sirupy, dark 
 brown liquid, gi\dng off a rancid, disagreeable odor. This 
 mallein is supplied in small vials of three sizes containing, 
 respectively, 1 cubic centimeter, 2 cubic centimeters, and 
 3 cubic centimeters of mallein. One cubic centimeter is 
 sufficient for testing 10 horses. Each bottle is dated, and 
 the mallein is not recommended for use longer than three 
 months after the date on the bottle. The bureau will be 
 in a position to fill orders promptly, therefore only suffi- 
 cient amounts for immediate needs should be requested. 
 Partly used bottles should not be kept over from one day 
 to another. The portion of mallein unused at the end of a 
 day should be discarded. 
 
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LTa3'iora Bros. 
 
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 Syracuse, N. V 
 
 PAT. JAN, 21. 1908 
 
LIBRARY OF CONGRESS 
 
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