Joelle Rosser

Fellowship Site: Kenya Medical Research Institute

US Institution: Stanford University

Dengue virus (DENV) is the most widespread arboviral disease worldwide, causing 390 million infections annually. Incidence of this potentially life-threatening infection has increased 30-fold in the last 50 years (WHO, 2012) due to urbanization, climate change, water insecurity, and inadequate vector control. Chikungunya virus (CHIKV), which causes post-infectious arthritis or neurologic sequelae in up to half of infected individuals, has also emerged recently. These arboviruses are spread by Aedes aegypti, an efficient vector that thrives in urban settings, particularly slum-like conditions with poor water infrastructure. Transmission is affected by human behaviors and environmental conditions. Mosquito density and vector competence for viral transmission are particularly influenced by rainfall and temperature. Recent laboratory models suggest the optimal temperature for DENV and CHIKV in Aedes aegypti is 29 °C, much higher than the 25 °C optimum modeled for malaria. A shift towards higher global temperatures could contribute to a shift from malaria to more arboviral infections across the African continent. LaBeaud recently validated the model of optimum temperature for malaria in Kenya. Under LaBeaud’s mentorship, I aim to evaluate the impact of temperature on DENV and CHIKV transmission at the GHES field sites in Kenya, comparing these empirical findings to Mordecai’s ecological model and potentially validating the important impact temperature has on vector-borne disease transmission in Kenya. Potential impact: Identifying optimal temperature ranges for DENV and CHIKV can help predict where these viruses may emerge in coming years with climate change. This would allow for increased surveillance, vector control planning, and medical provider training.