The pathogenicity of bacterium melitensis for guinea pigs

The very close relationship of B. abortus (Bang) to B. melitensis demonstrated by A. C. Evans 1 has been confirmed by our observations. Experimental studies, to be published in the near future, have furnished two additional characteristics of similarity.

1. The guinea pigs infected with B. abortus developed striking reactions of cutaneous hypersensitiveness with melitensis-protein, and vice versa in animals successfully infected with B. melitensis skin reactions are obtained with aborto-protein (see Table 1.).

2. In a series of attempts to infect guinea pigs with various known strains of B. melitensis obtained from the Hygienic Laboratory, U. S. Public Health Service (same strains as studied by Miss Evans), we finally succeeded in producing by intratesticular injection of 1/10 agar slant (48 hours'rrowth on peptic digest agar) a disease with pathological changes which could not be distinguished from those seen in about one hundred guinea pigs suffering from abortion disease. The lesions of two guinea pigs, which consisted of a very large spleen, general lymphadenopathy, liver and lung lesions with infiltrations of epithelioid cells and lymphocytes were only definitely diagnosed to be the result of a B. melitensis infection by cross agglutination and absorption

tests with the recovered bacteria. The observations thus far completed are summarized in Table 1. For comparison, the records of two guinea pigs successfully infected with the B. abortus, and four animals unsuccessfully inoculated intraperitoneally with B. melitensis are included.

Experiments with B. melitensis strains obtained from Algiers and with the B. paramelitensis (Nègre and Raynaud) are in progress.