A method has been devised whereby a prompt clear cut macroscopic agglutination for the diagnosis of glanders can be obtained in two hours.
Fifteen strains of B. mallei were tested and one obtained which is constant in its agglutinability with positive sera.
The best culture medium is glycerin-potato-agar (2.5 acid to phenolphthalein) carefully prepared (see text).
Great care must be used in the preparation of the stock suspension of B. mallei (see text). For the tests, fresh dilutions in 0.85 per cent salt solution are made from the stock suspension. No carbolic acid is added to the stock nor to the dilutions.
The agglutination test is valuable in the routine examination of horses. With this test nearly all early and acute cases can be detected and thus the spread of the disease can be prevented.
A negative reaction by a single agglutination test if not confirmed by the ophthalmic and the complement fixation tests does not prove the case negative; nor does a single negative result either by the complement fixation or ophthalmic tests. A positive reaction by any of the three methods is more significant than a negative one. All three tests must be performed in order to pronounce the horse negative.
In my experience with the present series of cases a reaction of less than 1:1000 by agglutination (if the other two tests are negative and if there are no clinical symptoms) is not indicative of glanders in the horse. If the reaction is above a 1:1000 the horse should be kept under observation; even if he does not show active glanders, the possibility of a carrier condition should be thought of. Isolation of such horses would be a very safe measure for preventing the infection among the other horses.
The bacteriological method of inoculating the guinea-pig with glanders material for the “Strauss” reaction is successful in only 25 per cent of cases (active lesions).
Autopsy findings, if possible, should be confirmed by pathological sections. A great many cases are pronounced glanders on autopsy, which do not show typical lesions under the microscope.
All stables should be under the supervision of the City Health Department and glanders in horses should be put in the same category as typhoid, meningitis, etc. in man, if glanders in New York City is to be eradicated. Sera that come to the Health Department for diagnosis should be accompanied by a complete history of each horse. Follow up work should be possible.
Records of the three tests and autopsy findings should be accessible and some mark of identification for every horse should be devised by which all records of a horse can be compared. Only in some such way can a really scientific study of the disease be made and the right conclusions drawn.