Perfil de resistência de Aedes aegypti (Diptera, Culicidae) de Contagem (Minas Gerais) aos inseticidas adotados nas atividades de rotina em saúde pública

Abstract

Aedes aegypti is one of the most important insect vectors of medical importance in Brazil, being the transmitter of arboviruses of major impact on public health such as Dengue, Zika, and Chikungunya. Given the impossibility of immunizing the susceptible population against these pathogens, vectorial control assumes a prominent position. In Brazil, the Ministry of Health recommends the use of mechanical control measures that comprise the elimination of the vector's breeding sites, associated with chemical control using insecticides. However, the continued exposure of these insects to these active agents has selected resistant populations of Ae. aegypti, directly impacting the incidence of the mosquito-related diseases. Therefore, this study sought to systematically review the literature on the accumulated knowledge regarding the resistance of Brazilian populations of Ae. aegypti to insecticides between the years 1995 and 2022. The searches were conducted in English, Portuguese, and Spanish in 7 scientific electronic databases. Descriptors catalogued in the Descriptors in Health Sciences and Medical Subject Headings were used, isolated and/or combined, in quotation marks, together with the Boolean descriptors "AND" and "OR". The search for studies, selection, and extraction of data were carried out independently by the two researchers, assisted by a third party in case of disagreements. A total of 741 studies were selected, of which 55 met the inclusion criteria. Of the 818 mosquito populations, 591 (72%) were resistant to any of the insecticides evaluated. Only 22 papers (40%) investigated mechanisms related to insecticide resistance having described biochemical alterations (esterases α, β, pnpa; cytochrome P450, acetylcholinesterase and glutathione-S-transferase) and mutations in the sodium channel gene (V1016I; F1534C and V410L). Additionally, a second objective of the present study was to investigate the resistance of Ae. aegypti, collected in the 8 health regions of Contagem, Minas Gerais, in the years 2019, 2021 and 2022 to different insecticides. The study region is heavily impacted by dengue, and, during epidemic periods, it is believed that the intensified use of insecticides is common and can contribute to the selection of resistant specimens. Bioassays were conducted in accordance with the World Health Organization. The insecticides evaluated were deltamethrin (technical grade) and the formulated products recommended for the control of Ae. aegypti larvicides SumiLarv® and NatularTM DT and adulticides KomvektorTM 440 EW, CieloTM ULV and Fludora®. In addition, the Alfatek® 200 SC currently recommended to combat adult sand flies was evaluated. Rockfeller was adopted as the susceptibility reference strain (SRL). The results were submitted to statistical analysis depending on the nature and distribution of the data. All populations were susceptible to all formulated insecticides used to control Ae. aegypti. On the other hand, all were resistant to Alfatek® 200 SC (mortality 30-45.5%), as well as to deltamethrin (larvae RR95 3.0-5.79; adults RR95 44.12 - 81.46). For all insecticides, there was no significant difference (p<0.05) in the susceptibility/resistance profile observed in comparisons of the 3 evaluation times. The results generated in this study unfold in practical directions to the actions of Ae. aegypti control in Contagem and may support the decision making of managers who oversee such activity, thus contributing to the strengthening of the Sistema Único de Saúde.