Abstract:

Objective To investigate the relationships and lag effects between Aedes albopictus density and meteorological factors, for scientific evidences for rational monitoring and early risk warning of mosquito-borne diseases. Methods Aedes albopictus surveillance data and concurrent meteorological records from April to October 2023 were collected in Jiading District, Shanghai. The mosquito ovitrap index (MOI) and landing index (LI) were used as indicators of Aedes albopictus density. The generalized additive model and the distributed lag nonlinear model were used to analyze the nonlinear effects of and lag effects between meteorological factors and Aedes albopictus density. Results From April to October 2023, Aedes albopictus density in Jiading District, Shanghai, showed significantly seasonal fluctuations. The logarithm of MOI was nonlinearly and positively correlated with daily average temperature (F=12.05, P<0.01) and daily minimum temperature (F=12.56, P<0.01), linearly and positively correlated with daily cumulative rainfall (F=9.32, P<0.05) and daily average relative humidity (F=10.60, P<0.01). The lag effects of meteorological factors on MOI were as follows: when the daily maximum temperature was 38.6 ℃, the relative risk (RR) peaked at lag 5 days (RR=2.5, 95%CI: 1.3-3.8); at a daily minimum temperature of 26.3 ℃, the maximum RR was observed at lag 5 days (RR=2.9, 95%CI: 2.6-3.3); under daily cumulative rainfall of 157.0 mm, the maximum RR was observed at lag 0 day (RR=1.6, 95%CI: 1.2-2.3); and at a daily average relative humidity of 52.1%, the maximum RR was observed at lag 0-1 day (RR=20.0, 95%CI: 12.1-38.5). The logarithm of LI was nonlinearly and positively correlated with daily average temperature (F=13.32, P<0.01), daily minimum temperature (F=13.63, P<0.01), daily cumulative rainfall (F=6.16, P<0.05) and daily average relative humidity (F=9.33, P<0.05), whereas showed linear and positive correlation with daily maximum temperature (F=9.76, P<0.01). The lag effects of meteorological factors on LI were as follows: at a daily average temperature of 15.0 ℃, the maximum RR was observed at lag 5 days (RR=57.5, 95%CI: 20.1-113.6); at a daily cumulative rainfall of 157.0 mm, the maximum RR was observed at lag 0 day (RR=7.8, 95%CI: 2.7-12.5); for daily average relative humidity, the maximum RR was 3.2 (95%CI: 1.5-4.9) at 88.0% with a lag of 5 days, and 6.7 (95%CI: 3.4-10.1) at 52.1% with a lag of 30 days. Conclusion The temperature, rainfall, and average relative humidity are associated with the density of Aedes albopictus in Jiading District, Shanghai, with temperature and rainfall showing obvious lagged effects on its density. It is recommended to combine meteorological factors with mosquito vector monitoring to guide local prevention and early warning of mosquito-borne diseases.

Key words: Aedes albopictus, Meteorological factors, Generalized additive model, Distributed lag non-linear model, Lag effect