Molecular epidemiological analysis of plague at the border area of Yunnan Province
This study was aimed at exploring the epidemiological characteristics of plague,and the evolutionary relation-ships among the isolated plague strains in the Yunnan border area,to provide clues for further studying epidemic causes and ep-idemiological patterns.Plague epidemic data in the border area during the second epidemic period(1982-2007)were collected and analyzed with descriptive epidemiological methods.Whole genome sequences of 262 strains of Yersinia pestis in the border area were obtained for phylogenetic analysis.Plague outbreaks occurred in 17 counties(cities)among 25 border counties(cit-ies);a total of 552 epidemic foci and 123 human cases were identified.The 1.ORI2,1.ORI3,1.IN3,2.ANT and 2.MED geno-types were identified among Yersinia pestis isolated from the Yunnan border area,among which the 1.ORI2 population was dominant.A total of 258 strains of Yersinia pestis from the 1.OR12 population belonged to four subclusters.The Myanmar and Vietnam clade was embedded within the Yunnan clade in the overall phylogeny.The above results indicated that during the sec-ond period of the epidemic,the intensity of plague epidemics in Yunnan's border areas was high,showing a trend of devel-opment from west to south and east.Our findings indicated a risk of cross-border transmission of plague between Yunnan and neighboring countries;therefore,the surveillance,pre-vention,and control of plague in border areas should be strengthened.
borderhouse rat plague focusYerisinia pes-tisgenomic epidemiology