Weather Factors Associated with Reduced Risk of Dengue Transmission in an Urbanized Tropical City

Abstract

IntroductionThe association of weather factors on dengue transmission in an urbanized tropical environment remains inconclusive. This study aims to assess the impact of weather factors on dengue incidence in Singapore between 2012 and 2019.MethodsData on weather variables (daily temperature, air quality, rainfall & wind speed) and weekly dengue incidence rates were collected from 1 January 2012 to 25 August 2019. Statistically significant correlated variables identified from cross-correlation analysis using Pearson’s correlation were examined in univariate ARIMA model. Quasi-Poisson model with a distributed lag non-linear model (DLNM) was established to assess any non-linear association between climatic factors and dengue incidence. FindingsPoor air quality (PSI: 150) and high wind speeds (12 km/h) were associated with reduced risk of dengue transmission in an urbanized tropical environment. Only a limited temperature range (27-32 °C and 23-25 °C) promotes dengue transmission whereas extreme heat inhibited dengue incidence (27°C, Ref. 25.14 °C; RR: 0.74, 95% CI: 0.58, 0.93). Rainfall exerts positive and negative influence alternately on weekly dengue cases across lags but the influence was not robust in sensitivity analysis. Based on split-sample model validation, mean temperature was the best predictor of dengue in prediction part (MAE: 43.15, RMSE: 51.39).