[Geographic distribution and feature of Yersinia pestis plasmid isolated from Yunnan province].

OBJECTIVE

To analysis the molecular-epidemiological feature of Yersinia pestis plasmid isolated from Yunnan.

METHODS

One thousand and twenty strains of Y. pestis isolates from 44 counties of Yunnan province in China and the border of China-Myanmar using Kado and Liu method and detected by agrose gel electrophoresis.

RESULTS

Results showed that these strains from Yunnan province carried 9 kinds of plasmids with molecular weights about 3.93, 6.05, 22.97, 35.65, 45.35, 64.82, 74.59, 111.36 and 129.55 x 10(6). Of these, three kinds of 3.93, 35.65 and 111.36 x 10(6) were found very specific, only reported in Yunnan. The plasmid profile could be divided into 10 types according to the plasmid content. Type I-V were common and had a clustering nature in geographic distribution.

CONCLUSION

Based on the plasmid profile, the epidemic districts of plague could be divided into several independent plague foci, suggesting that the resurgence of domestic rat caused plague epidemics might have several hidden plague foci as the result of epidemics since 1982 in Yunnan.