[Initial temperature for the development of Schistosoma japonicum larvae in Oncomelania hupensis].
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.
Sun
Le-ping
LP
Jiangsu Institute of Parasitic Diseases, Wuxi 214064.
Zhou
Xiao-nong
XN
Hong
Qing-biao
QB
Huang
Yi-xin
YX
Yang
Guo-jing
GJ
Xi
Wei-ping
WP
Jiang
Yu-ji
YJ
D000818:Animals; D006790:Host-Parasite Interactions; D007814:Larva / Q000254:growth & development; D012549:Schistosoma japonicum / Q000254:growth & development*; D012908:Snails / Q000469:parasitology*; D013696:Temperature