Meterologically Driven Dengue Fever Simulations in Sonora Mexico

Meteorological conditions strongly influence the ecology of mosquito-borne diseases. Ambient temperature is a primary regulator of mosquito development, reproduction, and mortality rates and also impacts the length of the virus extrinsic incubation period (EIP). Furthermore, precipitation is often an important source of water for creation and maintenance of habitat for mosquito eggs, larvae, and pupae. Consequently, climate influences the distribution of mosquito-borne diseases such as dengue fever (DF). DF is caused by infection with the dengue virus which is transmitted by Aedes genus mosquitoes, especially Aedes aegypti. However, although Ae. aegypti inhabits many of the urban areas of Sonora, MX, the distribution of the disease is uneven, with few locally acquired cases reported in the northern part of the state. This study uses mechanistic modeling of Ae. aegypti populations and dengue virus transmission dynamics to simulate cases of DF in two cities located in Sonora, Mexico: Hermosillo and Nogales. While Hermosillo experiences large annual variations in DF infections, local transmission of the virus is rare in Nogales. Dengue cases were simulated in Hermosillo from 2006-2015 and then in Nogales during the same time period. In Hermosillo, the simulattions replicated the reported DF case data accurately for most years and the model simulated few cases in Nogales, consistent with observations. Examination of the simulations revealed that temperature is likely responsible for the differences in simulated and observed DF cases between the two cities. The lengthening of the EIP, which is extended in the cooler Nogales climate, prohibits most mosquitoes from surviving the incubation period and therefore restricts virus transmission. When running the simulations for Nogales under projected future climate, however, warming temperatures shorten the incubation period and facilitate greater transmission of the virus. Therefore, because the EIP is largely regulated by temperature, risk of dengue virus transmission is likely to increase as temperatures warm, especially in areas inhabited by Ae. aegypti mosquitoes.