Ecologia e epidemiologia de flebotomíneos circulantes em áreas endêmicas no município de Seropédica, Rio de Janeiro

Abstract

Leishmaniasis represents a group of zoonotic, infectious diseases that put at risk more than 350 million people worldwide. Its transmission occurs during the blood feeding of females of sand flies infected by the etiological agent of the disease, the protozoan of the genus Leishmania. Due to the fundamental role played by the vector in the chain of transmission of the disease, the objective of this study was to evaluate the ecology and epidemiology of sandflies present in endemic areas for Leishmaniasis in the municipality of Seropédica. Sand flies were captured through a CDC-type light trap, located in peridomiciliary areas, for three consecutive days during a one-year period in five city neighborhoods, located in rural and peri-urban areas, where cases of Leishmaniasis detection in humans. Phlebotomines were identified for the species after the clarification and diaphanization process, according to Galati (2003). The indexes of temperature, relative air humidity and precipitation index were collected monthly on the site of the meteorological institute (INMET) and correlated with the number of specimens collected. An epidemiological questionnaire was applied to an owner of each residence where a trap was placed to obtain data about his knowledge about leishmaniasis and evaluation of environmental conditions and factors that contribute to the greater proliferation of sandflies. The main ecological data evaluated were of richness and abundance, using the coefficients of Shannon and Simpson; for statistical correlation, the Mann-Whitney and Kruskal-Wallis tests were used. A total of 17371 specimens were collected, identified in five species: Lutzomyia intermedia, Lutzomyia migonei, Lutzomyia pessoai, Lutzomyia whitmani and Lutzomyia fischeri. Of the specimens collected 57.5% (9984) were males and 42.5% (7387) were females. Valão das Louças was the site that presented the largest number of specimens collected (9096). The highest Shannon index was recorded in Campo Lindo (H = 0.7021) and the most abundant species was L. intermedia (69.1%). A significant difference was observed in relation to the number of sandflies collected in rural and periurban areas (p <0.0001) and in relation to the number of sandflies collected in the five districts studied (p <0.0048). The largest number of specimens was collected under conditions of 20 to 25ºC, between 75% and 85% of humidity and rainfall index of 0.0 mm. It was possible to observe that the greatest density of sandfly vectors predominated in rural areas and that some species of sand flies are more adapted to the peridomiciliary environment, such as L. intermedia. Thus, it is fundamental that epidemiological surveillance implement measures to control vectors in areas of higher risk to avoid future cases of cutaneous leishmaniasis in humans.