Heatwaves and dengue outbreaks in Hanoi, Vietnam: New evidence on early warning

This study aimed to compare the short-term temperature-dengue associations during different dengue outbreak periods, estimate the den gue cases attributable to temperature, and ascertain if there was an association between heatwaves and dengue outbreaks in Hanoi, Vietnam. Methodology/Principal findingsDengue outbreaks were assigned to one of three categories (small, medium and large) based on the 50th, 75th, and 90th percentiles of distribution of weekly dengue cases during 2008 –2016. Using a generalised linear regression model with a negative binomial link that controlled for temporal trends, temperature variation, rainfall and population size over time, we examined and compared associations between weekly average temperature and weekly dengue incidence for different ou tbreak categories. The same model using weeks with or without heatwaves as binary variables was applied to examine the potential effects of extreme heatwaves, defined as seven or more days with temperatures above the 95th percentile of daily temperature distribution during the study period. This stu dy included 55,801 dengue cases, with an average of 119 (range: 0 to 1454) cases per week. The exposure-response relationship between temperature and dengue risk was non-linear and differed with dengue category. After considering the delayed effects of temperature (one week lag), we estimated that 4 .6%, 11.6%, and 21.9% of incident cases during small, medium, and large outbreaks were attributable to temperatur...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research