The etiology and epidemiological significance of Yersinia pestis in Qilian County, Qinghai Province / 中华地方病学杂志

ABSTRACT

Objective To investigate the biological characteristics and epidemiological significance of Yersinia pestis strains in Qilian County,Qinghai Province,in order to provide a scientific basis for plague prevention and control.Method Totally 67 strains were separated from kinds of host in Qilian County,Qinghai Province from 1958 to 2011,to do biochemical test,toxicity test,virulence factors evaluation,plasmid analysis and different region (DFR) genotyping.Results According to biochemical typing,48 of the 50 strains tested were Qing-Tibet Plateau ecotype,15 were Qilian Mountain ecotype,and the remaining 4 were different ecotypes from the plague foci in Qinghai plateau.The strains had 8 genomovars,and were given priority to genomovar8 (42 strains),secondly,genomovar44 (15 strains),genomovar5 (4 strains),genomovar7 (2 strains),genomovar19 (1 strain),genomovar30 (1 strain),genomovar32 (1 strain),and genomovar34 (1 strain).A proportion of 95.52％ (64/67) of the strains contained 3 kinds of plasmid-6 × 106,45 × 106,and 52 × 106;85.07％ (57/67) contained all the four virulence factors,and 96.00％ (48/50) were velogenic strains.Conclusion The strains separated in Qilian County,Qinghai Province have the characteristics of Qinghai-Tibet Plateau plague's pathogen and have strong toxicity,so we should enhance the plague monitoring and give more publicity to plague prevention to prevent animal plague spreading to human.