Contribution to the Knowledgment of Feeding Habbits of Lutzomyia (Lutzomyia) Longipalpis (Lutz & Neiva, 1912) in Association to Natural Infection by Leishmania (Leishmania) Infantum Chagasi (Cunha & Chagas, 1937)

Abstract

Background: Brazil faces the expansion and urbanization of American Visceral Leishmaniasis. The presence of the vector in the urban area is one of the major challenges of the Brazilian Program for Control of Visceral Leishmaniasis, which refers the need for a better understanding the behavior of Lutzomyia longipalpis, as well as the factors of its adaptation to new habitats. The aim of the study was to combine diagnostic molecular tools capable to identifying natural infection by Leishmania (L.) infantum chagasi and the origin of food sources in L. longipalpis.Methods: The specimens were captured in the municipalities of Araguaína/Tocantins, Fortaleza/Ceará, Sobral/Ceará, and Rio de Janeiro/Rio de Janeiro. Molecular diagnoses were performed through Polymerase Chain Reaction using primers that amplify kinetoplast deoxyribonucleic acid in Leishmania sp. and the cacophony gene in phlebotomines for the diagnosis of natural infection, primers that amplify the cytochrome b gene, in addition to the sequencing technique, for the study of alimentary habit.Results: Among the analyzed females, 28.6% were diagnosed in the food evaluation. Among the total of 141 samples that were analyzed, showed a higher positivity for the human food source (62.5%), followed by dogs (27.5%) and birds (10%). In Araguaína, the samples showed positivity for human blood (61.5%) and dogs (38.5%). In Fortaleza and Sobral, specimens showed a positive percentage for human blood (54.5% and 66.7%), followed by dogs (27.3% and 20.0%) and birds (18.2% and 13.3%). In the females of Rio de Janeiro was detected exclusive feeding of human blood. In the natural infection, a general index of positivity was obtained equal to 4.3%. When associated, detection of the power source and natural infection, two infected specimens were found in Araguaína, with dog and human feeding; and in Sobral, 3 specimens infected and positive for human blood.Conclusions: The results corroborate with studies that demonstrate the eclecticism and food opportunism of L. longipalpis, as well as their occurrence in several environments, which are determinant factors of the important process of domiciliary vectorization. The low positivity feeding on human blood may suggest that other mammals, possibly rodents, would be acting as a food source.