title: [Molluscicidal effect of film on ditches in mountainous schistosomiasis endemic regions].
abstract: OBJECTIVE
  To evaluate the molluscicidal effect of film on ditches in mountainous schistosomiasis endemic regions.
  
  
  METHODS
  A ditch with Oncomelania hupensis snails was selected as experimental field. The ditch was divided into 3 parts (groups): a niclosamide plus film covering group (film covering after spraying by wettable powder of 50% niclosamide ethanolamine salt upon 2 g/m2), a film covering group (film covering directly without niclosamide spraying), and a control group (no molluscicidal measures). The snail investigation was performed 7, 10, 40, 60 d and 90 d after film covering. The temperatures outside and inside film were determined twice a day during the experiment.
  
  
  RESULTS
  The temperature inside the film was significantly higher than that outside the film (t = 4.12, P < 0.01). Compared with the densities of living snails before the experiment, the densities of living snails decreased by 99. 01% and 67.71% seven days post-film in the niclosamide plus film covering group and film covering group respectively; 96.58% and 93.06% ten days post-film respectively; both 100% forty days post-film. The multi-factor regression model indicated that covering film with niclosamide applying, extending film covering time, and increasing cumulate temperature inside film could enhance the molluscicidal effect.
  
  
  CONCLUSIONS
  The film covering has well molluscicidal effect. The molluscicidal effect of covering film with niclosamide is better than that of covering film alone in short time. However, the covering film alone also has good molluscicidal effect when increasing covering time.
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China.
authors.forename: Hong-Qing
authors.initials: HQ
authors.lastname: Zhu
authors.forename: Bo
authors.initials: B
authors.lastname: Zhong
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Zhang
authors.forename: Shu-Gui
authors.initials: SG
authors.lastname: Tang
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Cao
authors.forename: Xu-Dong
authors.initials: XD
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Jia
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Fu
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Ding
authors.initials: D
authors.lastname: Lu
authors.forename: Zi-Ping
authors.initials: ZP
authors.lastname: Bao
mesh_terms: D000818:Animals; D002681:China / Q000453:epidemiology; D004305:Dose-Response Relationship, Drug; D019353:Endemic Diseases / Q000517:prevention & control; D008975:Molluscacides / Q000633:toxicity*; D009534:Niclosamide / Q000633:toxicity*; D010571:Pest Control / Q000295:instrumentation / Q000379:methods*; D012424:Rural Population; D012552:Schistosomiasis / Q000453:epidemiology / Q000469:parasitology / Q000517:prevention & control*; D012908:Snails / Q000187:drug effects* / Q000254:growth & development / Q000469:parasitology
chemical_list: D008975:Molluscacides; D009534:Niclosamide