An analysis of surveillance results of dengue vector Aedes larvae in Jiangxi Province,China,2015-2022
Objective To investigate the density of the dengue vector Aedes larvae and its change over time in Jiangxi Province,China,so as to provide a theoretical basis for the prevention and control of dengue fever.Methods During May to October in 2015-2022,the density of Aedes larvae was monitored using the Breteau index(BI)method at 13 dengue vector surveillance sites in the province.R 4.3.1 software was used for data analysis.The container index(CI)for different container types was compared using the t test.The correlation between CI and house index(HI)and BI was determined through Pearson correlation analysis.The changes in annual average CI for different container types were analyzed using the Cochran-Armitage test for trend.Joinpoint 5.0.2 software was used to test the trend in annual average BI.Results From 2015 to 2022,the BI ofAe.albopictus larvae ranged from 5.88 to 15.36,CI ranged from 6.84%to 17.10%,and HI ranged from 4.73%to 10.69%.Except for a slight increase in 2016,the annual average BI in Jiangxi Province showed a downward trend as a whole.The CI of temporary containers showed a downward trend(Z=-18.514,P<0.001),and the overall level was higher than that of permanent containers(t=-2.739,P=0.029).The seasonal fluctuation of Aedes larvae showed a unimodal distribution,in which BI mainly peaked during May to June and then declined in every year.CI and HI showed basically the same changing trends as BI,and the correlation coefficients were 0.827(P<0.001)and 0.916(P<0.001),respectively.The annual average BI in northern and southern Jiangxi Province were higher than that in central Jiangxi Province.The monthly average BI was>10 from May to August and 5-10 from September to October.The number of surveillance sites with BI exceeding the transmission threshold was largest in 2019,and the number of surveillance sites with BI exceeding the transmission threshold was largest in June.Conclusions The overall density of Ae.albopictus in Jiangxi Province shows a downward trend,but there is still a risk of local transmission of dengue fever.It is necessary to strengthen integrated control against Ae.albopictus to reduce the risk of dengue outbreaks.
Dengue feverAedes albopictusEcological surveillanceBreteau index