title: [Sources of infection on human plague in Qinghai province].
abstract: OBJECTIVE
  To study the biological and genetic characteristics of 119 strains of Yersinia (Y.) pestis isolated from plague patients in Qinghai province, from 1958-2012.
  
  
  METHODS
  Both regular methods and different region(DFR)molecular typing techniques were used to study the epidemiological characteristics on 119 strains of Y. pesticin Qinghai during 1958-2012. Sources of Y. pestis from two outbreaks, in Nangqian county in 2004 and in Xinghai county in 2009,Qinghai province were also analyzed.
  
  
  RESULTS
  105 strains of Y. pestis were identified as Qinghai-Tibet Plateau Ecotype while the other 6 strains as Qilian Mountains Ecotype. 84.03% (100/119) of the tested strains carried 4 virulence factors F1(+), Pst I(+), VW(+) and Pgm(+)). 97.30% (72/74) of the tested strains showed high virulence. Strains that carrying 52×10(6), 65×10(6), 92×10(6) plasmids were distributed in Hainan, Haibei, Haixi,Yushu,Guoluo, Huangnan and Huangyuan counties. Genomovar 5 and 8 were the main gene types that circling around Qinghai Lake. Genomovar 10 was found in strains of Y. pesticin Nangqian county while Genomovar 8 was found in the strains isolated from human plague patient during the epidemics in Xinghai county in Qinghai.
  
  
  CONCLUSIONS
  Data from biological and genetic analyses on the epidemics of human plague in Nangqian county in 2004 and in Xinghai county in 2009 demonstrated that methods as DFR genotyping and virulence factors profiles, as well as plasmids profiles were powerful tools in confirming the human plague epidemics and sources of infection.
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Cunxiang
authors.initials: C
authors.lastname: Li
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Baiqing
authors.initials: B
authors.lastname: Wei
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Haoming
authors.initials: H
authors.lastname: Xiong
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Qi
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Youquan
authors.initials: Y
authors.lastname: Xin
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Rongjie
authors.initials: R
authors.lastname: Wei
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Jin
authors.affiliation: Qinghai Provincial Institute of Prevention and Control of Endemic Disease, Xining 811602, China. Email: drx200907@163.com.
authors.forename: Ruixia
authors.initials: R
authors.lastname: Dai
mesh_terms: D002681:China / Q000453:epidemiology; D005838:Genotype; D006801:Humans; D010930:Plague / Q000453:epidemiology* / Q000382:microbiology*; D015010:Yersinia pestis / Q000235:genetics* / Q000302:isolation & purification