Surveillance of important disease vectors in Zhejiang province

Objective To understand the annual dynamics of disease vectors such as rodents,mosquitoes, flies and cockroaches in Zhejiang province by analyzing the regularly surveillance data of disease vectors in Hangzhou, Ningbo and other 20 cities in 2008. Methods The night trapping and cockroach glue board methods were used to monitor the rodent and cockroach densities. The lamp -trapping and cage-trapping were conducted to monitor the densities of mosquitoes and flies from April to November, respectively. Results The annual density dynamic curves of mosquitoes and rodents were with single-peak, and the annual density dynamic curves of flies and cockroaches were with two-peaks. The density of rats was low. The constituent ratio of predominant mosquito species-Culex pipiens pallens was 61.9%, and the constituent ratio of Culex tritaeniorhynchus, Anopheles sinensis and Aedes albopictus reached about 21.0%, 6.0% and 3.3%, respectively in 2008. Blattella germanica (Linnaeus) was the predominant species and its constituent ratio reached 85.1% in 2008. The analysis by month indicated that the peak of mosquito density was during June July, two peaks of fly density were found to be in May and during July September, and two peaks of cockroach density were found too, which were during June-July and during September-October respectively. The density of rats changed greatly every month and peaked in April and in July. Conclusion IThe risk of vector-borne disease might be greater than before because of the change of vector population and its constitution.It necessary to strengthen the surveillance and control of disease vectors and vector-borne diseases in Zhejiang province.