Estimating the size of aedes mosquitoes’ population involved in outbreaks of dengue and chikungunya and its relationship with climatic factors

Background Aedes aegypti continues to cause large number of cases of dengue, chikungunya and zika fever in the affected areas of the tropical world. After being eradicated from Brazil in the decades if 1940 and 1950, Aedes aegipti returned with full force in the early 1970s. Knowing the total number of mosquitoes transmitting aedes-borne infections in crucial to quantifying the intensity of transmission of these infections. Methods In this paper, we propose a model to estimate the distribution of aedes mosquitoes’ population during an outbreak of either dengue or chikungunya. The model assumes that the mosquitoes’ distribution follows a Gaussian Mesa Function, which has five parameters and allows for a variable asymmetry. These five parameters are adjusted so that it fits indirectly, from a modified Ross-Macdonald model, the incidence of dengue or chikungunya infections (see main text). Results We illustrate the model with data of dengue and chikungunya from five cities from the State of Minas Gerais in the Southeastern region of Brazil for the 2023-2024 transmission season. In addition, we show that the calculated mosquitoes’ distribution correlates with climatic variables in the five cities studied. Conclusions The model shows that it is possible to estimate the size of the mosquitoes’ population from incidence data, circumventing the logistic hurdles involved in the actual counting of mosquitoes, and that the mosquitoes’ distribution correlates well with rain patterns in the studied cities, but not with temperature.