Hábito alimentar de lutzomyia longipalpis (diptera: psychodidae) em área de transmissão intensa de leishmaniose visceral no norte do Brasil

Abstract

Visceral leishmaniasis is an anthropozoonosis that has increased in number of cases in the northern region of Brazil. In the Americas, the disease is caused by the protozoan Leishmania infantum, which in Brazil is transmitted mainly by female sandflies of Lutzomyia longipalpis. The female acquires the protozoan during blood repast on an infected mammal and is subsequently transmitted after reproduction in the vector's intestine. The feeding preference of the species determines the hosts most at risk of infection. This study aimed to investigate the feeding habits of Lu. longipalpis, using molecular diagnostic methods through the amplification of mitochondrial DNA. Females of Lu. longipalpis were captured monthly for twelve consecutive months using CDC-type light traps installed in the intradomicile and peridomicile of eight neighborhoods in the urban area of Araguaína, Tocantins. The females collected were dissected, the head and the final third of the abdomen sectioned and mounted in Berlese liquid for identification. For DNA extraction, the thorax and part of the abdomen were used to form pools of up to 10 females, and conventional polymerase chain reaction (c-PCR) was carried out using primers that amplify regions of mitochondrial DNA (mtDNA) from human, dog, cat, and chicken. A total of 610 females were analyzed in 61 pools. A significantly higher frequency of positivity (P<0.05) occurred for human (47.5%) and dog (34.40%) DNA compared to chicken (13.10%) and cat (6.50%). DNA from two or more animal species was found in 42.6% of the samples analyzed. The results indicate that populations of Lu. longipalpis are present in peripheral and central regions of Araguaína, the vector visits the intradomicile to feed and has varied food sources, with frequent feeding on humans, warning of the risk of VL transmission when in the presence of an infected reservoir.