An analysis of malaria vector surveillance results in Anhui Province,China,2019-2022
Objective To investigate the population distribution,density,seasonal variation,and nocturnal activity patterns of malaria vectors in Anhui Province,China,so as to provide a reference for the risk assessment of transmission of imported malaria as well as the development of prevention and control strategies.Methods From 2019 to 2022,mosquito vectors were monitored at 20 surveillance sites in Anhui Province using light trap method and human-baited double net trap(HDN)method.Descriptive analysis was performed on the surveillance results.The Kruskal-Wallis H test was used to compare the number of Anopheles mosquitoes captured in different habitats and at different times,and the Bonferroni method was used for pairwise comparisons.Results From 2019 to 2022,a total of 31 322 and 12 306 Anopheles mosquitoes were captured by the light trap method and HDN method,respectively,all of which were morphologically identified as An.sinensis.The number of An.sinensis catches differed significantly between habitats in all the years(all P<0.001),with the largest number in the livestock and poultry sheds.The density of An.sinensis by HDN method showed a single peak during June to August.The densities of An.sinensis of each geomorphic area from low to high is as follows:0.32 mosquitoes/person·h in the northern Huai River plain area,1.63 mosquitoes/person·h in the Yangtze River plain area,1.73 mosquitoes/person·h in the Jianghuai hilly area,and 2.13 mosquitoes/person·h in the southern Anhui mountainous area mosquitoes/person·h,respectively.The peak hours of Anopheles sinensis nocturnal activity in different geomorphological areas are different,and the peak nocturnal activity occurs at 20:00-<22:00 in the Huaibei Plain and Yanjiang Plain,23:00-<01:00 in the Jianghuai hills,and 19:00-<21:00 in the mountainous areas of southern Anhui.Conclusions An.sinensis is the dominant species of malaria vectors in Anhui Province,and the mosquitoes are densely distributed in mountainous and hilly areas and the Yangtze River plain area.It is recommended to stratify the risk of malaria re-transmission throughout the province on the basis of vector Anonpheles surveillance results and the distribution characteristics of and imported malaria,so as to precisely guide the implementation of prevention and control measures.