306 - Mapping Urban Mosquito Microhabitats and Malaria Risk Using Satellite Earth Observations

Anopheles stephensi is associated with urban habitats and is an important malaria vector throughout its native range in South and West Asia. This species is currently spreading into Africa, raising concerns that it could establish new foci of urban malaria transmission throughout the continent. Better neighborhood-level maps of mosquito habitat suitability and malaria transmission risk are needed to inform vector control and malaria elimination in cities. Satellite Earth observations can support these efforts by providing high-resolution maps of buildings, vegetation, and water as well as direct measurements of land surface temperature. We used satellite data to analyze urban heat and moisture island effects in Ahmedabad and Surat, two malaria-endemic cities in western India. Land surface temperature data were obtained from the ECOSTRESS instrument, and land cover data were generated through time series analysis of Landsat data. In situ temperature and humidity data were collected using microclimate sensors located indoors and outdoors at 93 dwellings in the two cities. Outdoor temperature and relative humidity were generally higher in the urban core than at the periphery, but these patterns were weaker for indoor locations. Microclimate patterns were associated with land cover and land surface temperature, particularly concentrations of impervious surfaces and areas of irrigated agriculture. Predictions of Anopheles stephensi vectorial capacity exhibited strong spatial variation, and hot spots of high malaria transmission potential shifted throughout the season. These results demonstrate how combining satellite Earth observations with ground-based microclimate measurements can provide valuable data to support urban malaria control programs.