title: [Natural growth and decline of Oncomelania hupensis snails in marshland of Qianliang Lake District in Eastern Dongting Lake area, China].
abstract: OBJECTIVE
  To understand the change trend of Oncomelania hupensis snails in the bottomland areas of Qian Liang Lake district in Eastern Dongting Lake area so as to provide the evidence for formulating a schistosomiasis control strategy.
  
  
  METHODS
  The monitoring data of snails of Qianliang Lake district from 1988 to 2011 were collected retrospectively and analyzed by using the method of the trend Chi-square test. The correlations among the snail density indicators were analyzed.
  
  
  RESULTS
  1988 to 2011, the area of snails surveyed did not change and was 433.2 hm(2). The monitoring data showed that the change trend of the density of living snails and the schistosome infection rates of snails were not obvious (P > 0.05), but the mortality of snails showed a falling trend (P < 0.05); There were positive correlations between the average density of infected snails and the mortality of snails (r = 0.640, P < 0.05) , the infection rate of snails (r = 0.639, P < 0.05) , and the average density of living snails (r = 0.646, P < 0.05) , respectively. There was no correlation among other snail indicators. In 1999, only 7 snails were found, of them, only one snail was alive. The alive snails were not found after 2000.
  
  
  CONCLUSIONS
  In the bottomland areas of Qianliang Lake district, the change trend of the density of alive snails were not obvious from 1988 to 1998, but the number of snails underwent a sharp drop in 1999 and snails have been not found till now.
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Lin-han
authors.initials: LH
authors.lastname: Li
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Yi-biao
authors.initials: YB
authors.lastname: Zhou
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Bao-dong
authors.initials: BD
authors.lastname: Yao
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Jin-yi
authors.initials: JY
authors.lastname: Wu
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Sheng-bang
authors.initials: SB
authors.lastname: Zheng
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Xiu-xia
authors.initials: XX
authors.lastname: Song
authors.affiliation: Junshan Anti-schistosomiasis Office, Yueyang City, Hunan Province, China.
authors.forename: Zhongz
authors.initials: Z
authors.lastname: He
authors.affiliation: Qianliang Lake Anti-schistosomiasis Station, Yueyang City, Hunan Province, China.
authors.forename: Jia-bian
authors.initials: JB
authors.lastname: You
authors.affiliation: Junshan County Anti-schistosomiasis Station, Yueyang City, Hunan Province, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Cai
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Gen-ming
authors.initials: GM
authors.lastname: Zhao
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Ministry of Education, Shanghai 200032, China.
authors.forename: Qing-wu
authors.initials: QW
authors.lastname: Jiang
mesh_terms: D000818:Animals; D002681:China; D004197:Disease Reservoirs / Q000469:parasitology; D006801:Humans; D060106:Lakes / Q000469:parasitology*; D011157:Population Dynamics; D012547:Schistosoma / Q000502:physiology; D012552:Schistosomiasis / Q000469:parasitology / Q000517:prevention & control*; D012908:Snails / Q000254:growth & development* / Q000469:parasitology; D053833:Wetlands