RELATIONSHIP BETWEEN RAINFALL AND CONTROL EFFECTIVENESS OF THE AEDES AEGYPTI POPULATION THROUGH A NON-LINEAR DYNAMICAL MODEL: CASE OF LAVRAS CITY, BRAZIL

摘要

Despite the efforts spent to control the dengue vector, Aedes aegypti, by public managers and society, many cases of dengue have been reported periodically in the world, mainly in tropical and even subtropical regions. Although the budget of government agencies for the control of this vector has been growing every year worldwide, in most countries these resources are often scarce. It is, therefore, desirable to improve the effectiveness of the control actions of Ae. aegypti population to acceptable levels in the environment. Among the possible actions to maximize this efficiency, there lies the determination of the best period of year to perform the public health control actions. In Brazil, unlike the actions recommended by the Ministry of Health to provide control in the beginning of wet seasons, experts conjecture that this period of the dengue vector control should be advanced to the cold and dry seasons. By such purposed approach, there are expectations in to occur the decrease in the number of infections of dengue fever in the subsequent wet season, thereby incurring a lower cost and lower economic social impact. In order to validate the above conjecture, it is proposed and analyzed a mathematical model composed of four populations expressed through non-linear differential equations to describe the population dynamics of the life stages of development of the Ae. aegypti. The coefficients of the model are set to be dependent to the rainfall index. In this model, it is possible to implement the control in any week of the year, and to compare their relative efficacies. The model was evaluated by using the actual rainfall data of city of Lavras-Minas Gerais, Brazil. The model is numerically solved with MATLAB R2009b.