IMMUNIZATION TESTS WITH GLANDERS VACCINE. 3 



four months not a single case of glanders developed, although in the 

 meanwhile 14 cases of glanders developed among 300 nonimmunized 

 animals. 



Bautz and Machodin subjected farase to various tests to establish 

 its immunizing value. Their results on guinea pigs, cats, and horses 

 were very satisfactory. Guinea pigs which were given two injections 

 of farase resisted six weeks later an intraperitoneal infection with 

 1/2500 and 1/5000 mg. of glanders bacilli. Of six horses which 

 received two immunizing injections of farase, two were given 1/2500 

 mg. of glanders bacilli subcutaneously, two received 1/500 mg. of 

 glanders bacilli per os, and two were exposed with the other animals 

 45 days after the second injection. For each of the groups one check 

 was used. Post-mortem examination of the check animals four to 

 five weeks after the infection showed typical glanders, while the two 

 immunized animals which received subcutaneous injections of 

 glanders bacilli failed to show any lesions of the disease. No record 

 was obtained of the four remaining immunized animals, as they were 

 turned over to another laboratory for study of the duration of immu- 

 nity in these horses. 



One of the recent works on the immunization of glanders was pub- 

 lished by Zurkan, who studied the formation of specific antibodies in 

 the blood of horses under the action of glanders antigens. He con- 

 cludes that of various antigens such as farase, killed glanders bacilli, 

 mallein, and malleo-aggressin, the first and the last (farase and malleo- 

 aggressin) proved most active in the production of immune bodies. 

 The degree of immunity in the animals was established by Zurkan 

 from the comparative results of the serological reactions he obtained 

 with the complement-fixation, agglutination, precipitation, and 

 opsonic tests. Since there were no practical tests made on these 

 animals, his statement that malleo-aggressin may be used for the 

 immunization of horses against glanders can not be accepted as 

 conclusive. 



At the meeting of the American Veterinary Medical Association in 

 Indianapolis, MacKellar presented his conclusions on the protective 

 effect of glanders vaccine. The proportion of infections in the stables 

 where these outbreaks occurred, as indicated by the agglutination 

 test, is astonishing. As there is no mention made in the article of the 

 time the agglutination tests were applied subsequent to the mallein 

 test, it suggests that the large proportion of reactors to the agglutina- 

 tion test were the result of the mallein injection and not due to the 

 presence of the infection. If this be true, then the effect of the 

 vaccine remains indefinite and the control of the disease must be 

 accredited to the other precautions which were observed. At best it 

 will require several years before the value of any method of immu- 

 nization can be satisfactorily established. 



