[The development of morphologic changes and the antibody response in guinea pigs experimentally infected with...

Sixty-two guinea pigs were infected vaginally, perorally, intranasally, conjunctivally and subcutaneously with the bacteria B. suis, biotype 2. The inoculum contained 13.8.10(9) of brucellas in 1 ml of physiological solution. Subcutaneous infection lasted 151 days, the other types of infection 56 days. All types of infections resulted in brucellotic changes developing in relation to the type and duration of infection. The least marked changes were observed after peroral infection. Brucellosis was chronical and the changes in liver, spleen, lungs, and after subcutaneous infection also in regional lymphoglandulae, were found out incessantly. Microscopically these changes were histiocytic granulomas. The pathogenesis of brucellosis process in guinea pig organism is influenced primarily by haematogenous propagation. The highest serological reactivity was caused by subcutaneous infection, the lowest by peroral infection. In the course of different types of infection the titres of agglutination and complement-fixation antibodies varied and the highest values were recorded between the 21st and 56th day. The diagnostic effectiveness of the surface fixation test was verified and no decrease in its sensitivity, not even in the chronic phase of infection, was observed. An incomplete correlation between morphological changes and serological reactivity in guinea pigs was detected. The highest number of Brucella infections was identified by histopathological examination which helped to reveal the initial stages of granulomas at the time when specific antibodies were not yet determined by serological tests.