Emerging combinations of climatic parameters for dengue proliferation in urban landscapes

Ectotherm insects growth and development are dictated by temperature and humidity. Conducive habitats and the availability of resources set ideal conditions for insect population growth. Mosquitoes require water, favorable temperature, and blood meal to survive. In this research, we picked a rapidly growing megacity, Ahmedabad, in western India, to explore and establish potential linkages between disease spread and meteorological conditions. Ahmedabad, with a population of over 8 million, is experiencing changes in rain and humidity patterns, pushing the city towards changing vector-borne disease dynamics. We examined dengue cases over ten years, 2012-22, and explored their connections with two prominent climatic variables, temperature and relative humidity. Our findings indicate that stable temperature (25-27.5 {degrees}C) and humidity (> 60%) interaction is a ruling factor in spikes in dengue cases in the city. While stable temperature ranges triggers the dengue cases, RH drives the explosive phases and sustainability of such episodes. Statistically significant increasing trends in temperatures, narrowing down of the day-night temperature ranges, and increasing night temperatures provide more stable temperature regimes in a warming world thereby likely to extend the dengue season beyond the usual monsoon season. Plain Language SummaryDengue incidences have been found to be associated with mosquito population outbreaks. Every year, thousands of lives are lost due to this deadly virus spread by mosquitoes. Particularly in the Indian subcontinent, a large proportion of these cases is associated with the monsoon season and rain patterns. In recent years, there have been abrupt spikes in dengue cases across Indian cities, particularly in western India. To understand this complex interaction of viral proliferation and local environmental conditions, the last ten years of dengue case patterns have been scanned in parallel to the climate data. Our findings suggest that stable temperature windows and humidity levels above certain thresholds trigger a rise in dengue cases. While stable temperature ranges trigger dengue cases, humidity drives such episodes explosive phases and sustainability. Our work pinpoints specific temperature-humidity combinations and suggests that local municipal corporations use them as warning indicators to initiate preventive measures.