Plague diagnosis: reverse indirect hemagglutination assay versus bacteria culture

Objective To select a sensitive, simple and rapid method for diagnosing plague by comparing the results of reverse indirect hemagglutination assay (RIHA) with that of bacteria culture. Methods Mice, guinea pigs and rabbits were infected with Yersinia pestis and died, their liver and spleen were sampled. At room temperature (18～22℃), the bodies of rabbit became decayed naturally, their spleen was sampled on 0,15, 60 days respectively. Meanwhile lung from human corpse infected Yersinia pestis was taken. All the samples mentioned above went on RIHA and bacteria culture at the same time, then the positive rate of Yersinia pestis was calculated to compare the effects of detecting Yersinia pestis. Results After infected with Yersinia pestis, the positive rate of Yersinia pestis from animal and human samples by RIHA (100%) is obviously superior to that of bacteria culture (87%). RIHA method was also obviously superior to that of bacteria culture in detecting decayed samples when Yersinia pestis culture showed negative, for it could detect the antigen of Yersinia pestis with an antibody liter of 1 : 102 400. Conclusions RIHA, sensitive, simple and rapid in plague diagnosis, can make contribution to confirming the existence of plague and evaluating the plague prevalence. In practical work, It may become one of experimental criteria for early plague diagnosis.