Investigation on mosquitoes in early spring in pig house of Shanghai Fengxian area

Objective To understand the constitution of mosquitoes, the situation of sucking blood and natural change of Culex tritaeniorhynchus , major vector of Japanese encephalitis virusl, in pig house at north temperate zone in early spring ,and to provide science basis for monitoring Japanese encephalitis and preventing mosquitoes. Methods To investigate mosquitoes in early spring in pig house of Fengxian Chenhebang in Shanghai from March 1,2002 to May 31,2002. Results (1)8 268 collected mosquitoes belonged to 8 species and 4 genus.(2) 5 956 Culex tritaeniorhynchus was 72.04% of the total. The rate of sucking blood was 62.83% .(3)The first group of Culex tritaeniorhynchus appeared on March 11,2002, and there were multiparous and pregnant mosquitoes among them. Conclusion Culex tritaeniorhynchus was superior among mosquito species in local pig house, and it is possible that Culex tritaeniorhynchus has migratory character. Natural increasing speed of Culex tritaeniorhynchus in early spring was slow at first and accelerated later, which it was related to the change of climate and environment closely.