A Serological Study of Undulant Fever in Southern Rhodesia

Abstract

1. Examination of nine type strains of Brucella, collected from various sources, by agglutination and the absorption of agglutinin test revealed distinct serological difference between Br. abortus and Br. melitensis. Differentiation could only be made by the agglutinin-absorption test, both organisms agglutinating equally with abortus or melitensis immune sera.2. By agglutination alone differentiation could be made between a group consisting of Br. melitensis and Br. abortus strains on the one hand and a group which included one strain labelled Br. melitensis, one labelled Br. abortus, and Br. paramelitensis.3. The agglutinin-absorption test showed that this Br. paramelitensis group comprised two strains of closely allied paramelitensis strains, and that the Br. abortus strain could be regarded as a Br. para-abortus strain.4. Serological investigation of eight strains of Brucella isolated from patients suffering from undulant fever in Southern Rhodesia showed that six were serologically identical with type Br. abortus and two identical with what is regarded as a Br. para-abortus strain.5. It is suggested that the melitensis-abortus group represent the “S” normal types, whereas the paramelitensis-para-abortus group represent the “R” mutant types of organisms.