title: [Initial temperature for the development of Schistosoma japonicum larvae in Oncomelania hupensis].
abstract: OBJECTIVE
  To study the impact of environmental temperature on the development of Schistosoma japonicum larvae within the Oncomelania hupensis.
  
  
  METHODS
  Oncomelania snails, collected from the field and free of S. japonicum infection, were exposed to miracidiae of S. japonicum in a ratio of 1:20 and raised at 30 degrees C, 27 degrees C, 24 degrees C, 21 degrees C and 18 degrees C, respectively. The prepatent period of larvae within the Oncomelania hupensis and the developmental velocity were determined, of which the relationship with the temperature was analysed.
  
  
  RESULTS
  The average prepatent period of cercariae in snail was (128.89 +/- 16.05) d, (95.00 +/- 21.03) d, (71.93 +/- 12.74) d and (62.74 +/- 14.19) d at 21 degrees C, 24 degrees C, 27 degrees C, 30 degrees C, respectively. The regression formulation between prepatent period and temperature was y = 730.68x(-0.8918) (r = 0.9976, P < 0.01). And the regression formulation between developmental velocity of S. japonicum larvae in snail and temperature was y = 0.0235ln(x) -0.0639 (r = 0.9973, P < 0.01). It was derived that the unitial temperature for the development of S. japonicum within the snails was 15.17 degrees C +/- 0.43 degree C.
  
  
  CONCLUSIONS
  The development of S. japonicum larvae within the Oncomelania snails declines with the decrease of temperature.
authors.affiliation: Jiangsu Institute of Parasitic Diseases, Wuxi 214064.
authors.forename: Le-ping
authors.initials: LP
authors.lastname: Sun
authors.forename: Xiao-nong
authors.initials: XN
authors.lastname: Zhou
authors.forename: Qing-biao
authors.initials: QB
authors.lastname: Hong
authors.forename: Yi-xin
authors.initials: YX
authors.lastname: Huang
authors.forename: Guo-jing
authors.initials: GJ
authors.lastname: Yang
authors.forename: Wei-ping
authors.initials: WP
authors.lastname: Xi
authors.forename: Yu-ji
authors.initials: YJ
authors.lastname: Jiang
mesh_terms: D000818:Animals; D006790:Host-Parasite Interactions; D007814:Larva / Q000254:growth & development; D012549:Schistosoma japonicum / Q000254:growth & development*; D012908:Snails / Q000469:parasitology*; D013696:Temperature