Investigation On Mosquitoes And Study On Natural Infection Of The Epidemic Encephalitis B Virus Of Culex Pipiens Pallens And Culex Tritaeniorhynchus In Dalian

ObjectiveThe Epidemic Encephalitis B is internationally called Japanese Encephalitis(JE), which is mainly popular in Asia.Its pathogen is JE virus.At present,thousands of people all over the world die of this kind of disease every year.A large number of researches and papers have focused on the vector of the Epidemic Encephalitis B.And it has been proved that mosquitoes are the main vector.The mosquitoes separated from the natural ones,which carry JE virus,are more than 5 genera 30 species around the world.Up to now,we can find 5 genera 17 species in our country:Ae(S.)albopictus, Ae.chemulpoensis,Ae.(O.)dorsalis,Aedes lineatopennis,Ae.(Aedimorphus)vexans, An.(A.)sinensis,An.(Cel.)pattoni,Armigeres subalbatus,Culex annulus,Culex fuscocephalus,C.(Ba)modestus,C.(C.)pipiens pallens,Culex pipens quinquefasciatus, Culex pseudovishnui,C.(C.)tritaeniorhynchus,Culex whitmorei,Mansonia uniformis. In the north of China C.(C.)pipiens pallens is the main vector of the Epidemic Encephalitis B,followed by C.(C.)tritaeniorhynchus.These two kinds of mosquitoes are also the main vectors in Dalian.C.(C.)tritaeniorhynchus is the main vector among the domestic animals and C.(C.)pipiens pallens is the main vector between human beings and domestic animals.We investigated on the basic situation of mosquitoes and studied on the natural infection of the Epidemic Encephalitis B virus of Culex pipiens pallens and Culex tritaeniorhynchus in Dalian from May to October in 2007.And these can help to provide certain theory foundations to explore the epidemic regularity of the Epidemic Encephalitis B virus in nature.Materials and MethodsWe have investigated on the basic situation of mosquitoes and studied on natural infection of the Epidemic Encephalitis B virus of Culex pipiens pallens and Culex tritaeniorhynchus in Dalian.Human baited net trap method,lamp baited trap method,and larvae collection method were used and the virus was identified with RT-PCR.ResultsMosquitoes collected in Dalian include 3 genera 9 species:one species called Anopheles,four species of Aedes,and four species of Culex.Mosquitoes come forth in May,reach the peak in August,decline gradually in September and disappear in October.Human beings are attacked mainly by Culex pipiens pallens(47.98%),Ae.(F.) togoi(12.15%)and Ae.(O.)dorsalis(10.41%).Culex and Anopheles take actions at night and,Aedes prefer daylight.Different mosquitoes density in different occasions reflect the various features of mosquitoes:Culex pipiens pallens,C.(Ba) modestus,Ae(S.)albopictus choose human blood,C.(C.)pipiens pallens prefer pigs' and cows' blood as well,C.(C.)tritaeniorhynchus especially like pigs' blood, An.(A.)sinensis choose cows' blood,Ae.(O.)dorsalis and Ae.(Aedimorphus)vexans are fond of pigs' and cows' blood.The Epidemic Encephalitis B virus was first found on August 16^th.70 groups of samples were examined,including 4.28%male mosquitoes.Conclusion1.Culex pipiens pallens,Ae.(F.)togoi and Ae.(O.)dorsalis are dominant threat to the inhabitant in Dalian..2.The natural infection of encephaitis B virus of mosquitoes begins from mid August.Culex tritaeniorhynchus is the first infected species. 3.The investigation provides some basic foundations for the control of mosquitoes and gives a scientific support for the prediction of the happening time and prevalence intension of the Epidemic Encephalitis B virus.