Climate extremes increase dengue risk along elevation and socio-economic gradients in Colombia

Globally, urban settlements face increases in the frequency, magnitude, and duration of extreme climate events and shifts in their timing and spatial extent. Variation in temperature and rainfall conditions affect the temporal onset of dengue transmission. However, there is a need to understand how climate-related patterns and disease transmission mechanisms vary by location, particularly for topographically complex landscapes. In this investigation, we used dengue cases from 1,120 municipalities and five regions across Colombia during 2008-2019, and analyzed associations with extreme climate covariates generated from fine-scale, daily-level meteorological data, accounting for varying landscape and socio-economic properties. Using Bayesian spatio-temporal hierarchical models, we determined that high-intensity warm spells (with positive temperature anomalies of 8-12{degrees}C above mean monthly conditions) resulted in an earlier onset of dengue transmission risk in high-elevation settlements compared to low- elevation settlements. Furthermore, the risk of dengue transmission after extremely dry conditions was greater and extended for a longer duration in highly urbanized municipalities compared to those with a low urban population. Our findings highlight that meteorological hazards affect disease transmission in urban settlements differently based on elevation and socio-economic conditions. Additionally, our analysis adds to increasing evidence of the vulnerability of mountainous urban communities to extreme weather and vector-borne diseases. Overall, we emphasize the need for monitoring and forecasting the occurrence and intensity of meteorological hazards and associations with emerging climate-sensitive disease threats.