title: [Influencing factors of changes of Oncomelania snail densities in Poyang Lake region, Nanchang City, 2011].
abstract: OBJECTIVE
  To explore the influencing factors of the significant decrease of snail densities in Poyang Lake region, Nanchang City, 2011.
  
  
  METHODS
  According to the elevation of the environment, 5 grasslands where there were high snail densities and their elevations were from 14 to 17 m were selected as study areas. The data of snails in the past three years and the hydrological information in the past five years were collected and analyzed. The current snail status was surveyed and the fishermen were interviewed.
  
  
  RESULTS
  The snail density of Poyang Lake region in Jinxian County decreased by 91.2% in 2011 compared with that in 2009 (P < 0.01). In 2010, the water levels were 13.90 m in April and 16.07 m in May respectively in Xingzi Station, and the rainfalls were 312 mm in April and 356 mm in May in Poyang Lake region; in 2011, the water levels were 8.73 m in April and 10.31 m in May respectively in Xingzi Station, and the rainfalls were 90 mm in April and 145 mm in May respectively in Poyang Lake region, which were lower than those during the past five years. There was no any other apparently unusual phenomenon.
  
  
  CONCLUSIONS
  The significant decrease of snail densities in Poyang Lake region in 2011 may be related to the long soaking time of marshland in 2010 and low rainfall in the first half of 2011.
authors.affiliation: Nanchang Center for Disease Control and Prevention, Nanchang 330038, China.
authors.forename: Yi-Sheng
authors.initials: YS
authors.lastname: Zhou
authors.forename: Guo-Hua
authors.initials: GH
authors.lastname: Peng
authors.forename: Zhu-Hua
authors.initials: ZH
authors.lastname: Hu
authors.forename: Rong
authors.initials: R
authors.lastname: Zhu
authors.forename: Qing
authors.initials: Q
authors.lastname: Yu
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Cao
authors.forename: Guang-Han
authors.initials: GH
authors.lastname: Hu
authors.forename: Jia-Gang
authors.initials: JG
authors.lastname: Guo
mesh_terms: D000818:Animals; D004777:Environment; D060106:Lakes / Q000469:parasitology*; D011156:Population Density; D012307:Risk Factors; D012908:Snails / Q000254:growth & development* / Q000469:parasitology; D014887:Weather