对阿拉善黄鼠实验感染鼠疫的研究

An Experimental Infection of Citellus alaschanicus with Yersinia pestis

Rodents (Citellus alaschanicus) from plague endemic area and non-plague area were experimentally infected with Yersinia pestis. The results showed that the organism number at lower limit of LD after challenge was 100000 times as much as that at upper limit of LD in the animal group from plague endemic area and the number 1000 times as that in the animal from non-plague area, indicating that the animals from plague area may be more naturally resistant to Yersinia pestis, and that persisting type of the bacteria-carrying process existed in the hibernating rodents from plague area under the experimental condition and that the rodents from non-plague endemic area were highly susceptible and sensitive to Yersinia pestis and the persisting type of the bacteria-carrying process did not exist in the survivals of them and no Fl antibody was detected in the sera from the survivals. This may confirm that Citellus alaschanicus from Haidong District of Qinghai Province does not act as a plague reservoir. The fact that Citellus alaschanicus was found to be able to carry the causative agent of plague over winter time under the experimental infection may supply some valuable data for approach to the bacteria-preserving mechanism. Furthermore, the study also showed that symptomatic manifestations occurred in these rodents after infection with Y. pestis were characterized by acute attack, incubation period of 1-2 days (the shortest incubation period was 12 hours), anorexia, standing-up hairs on the back of the animals, shortness of breath, and the enlargement of lymph nodes at injection sites after inoculation and that pathological changes, which were mainly characterized by hemorrhagic inflammatory reactions in the animals, became severer with the increase of challenging dose, the pathological changes being mainly hyperplastic with low challenging dose, and those mainly exudative, hemorrhagic and necrotic with high challenging dose.