Entomological surveillance for phlebotomines in the metropolitan region of Aracaju, Brazil

Abstract

Records of infections by Leishmania spp. (Kinetoplastida: Trypanosomatidae) have been occurring in the last decade in Sergipe, Brazil. The capital, Aracaju, alone accounted for 44% of the total cases of the state for the visceral form between 2007 and 2016, with high numbers also in other municipalities that make up the metropolitan region. In this sense, this work aimed to carry out entomological surveillance actions in the municipalities of the Metropolitan Region of Aracaju and evaluate the characteristics of the peri-domestic environments that contribute to the maintenance of species richness and abundance. Entomological captures were carried out between 2021 and 2022 with Centers for Disease Control and Prevention (CDC)-type traps for three consecutive nights between twilight and dawn at the beginning of the dry and rainy periods in the peri-domestic area of residences in neighbourhoods peri-urban in the municipalities in the metropolitan region: Aracaju, Barra dos Coqueiros, Nossa Senhora do Socorro and São Cristóvão. The characteristics around the houses were also recorded in a field diary. Constancy, dominance for all species, the household infestation rate and the relative abundance index of the vector for epidemiologically interesting species were calculated. Chi-square tests and multivariate analyses of variance were also performed to search for associations between the vectors and aspects of the dwellings. In total, 752 phlebotomines were captured at 64 collection points. Seven species of phlebotomines were identified, including Lutzomyia longipalpis (Lutz & Neiva, 1912), Evandromyia lenti (Mangabeira, 1938) and Migonemyia migonei (França, 1920). The vector Lu. longipalpis was the species that showed the highest infestation in residences. The results also reveal a sex-specific association influenced by vegetation size, suggesting that denser vegetation may promote male aggregation, a behavioural trait that could be explored in the development of targeted vector control strategies. No significant association was recorded between abundance and environmental factors, which may be related to the difficulty of measuring this association in a heterogeneous environment with so many anthropic interferences in the urbanisation process. By evidencing the influence of ecological factors such as vegetation size on vector behaviour, this study offers insights to enhance leishmaniasis control strategies in Sergipe.