Evaluation of feeding habits of Lutzomya longipalpis in the State of São Paulo

Abstract

 We evaluated the feeding habits of Lutzomyia longipalpis in areas in which American visceral leishmaniasis is     occurring, in the city of Araçatuba, in the State of São Paulo. During the period comprised between 1999 to 2001,     monthly entomologic captures were performed in three areas of the city, and 123 residences/area were     researched for samples, spending 20 minutes at each household. Ingurgitated females were separated and     preserved at -20°C, until performance of the exam of their intestinal contents, by the immune-precipitate reaction     in capillary tubes. We used anti-sera from: pets (dog, horse, cat and hen), rodents and human beings. For the     performance of the reaction, each female was placed in a tube with 0,2mL os sterile physiological solution with     merthiolate at 0,85%, for 12 hours. Later, they were macerated and centrifuged and 30ml of the surfacing was     transferred for the capillary tube and added 30ml of anti-sera. Reaction was considered positive when a whitish     clot up until two hours after the start. We collected 1540 L. longipalpis females and, among these, 699 were     ingurgitated at collection and 613 (87,7%) were submitted to the test, resulting in 45,6% of reactive samples.     Among the reactive samples, 91,4% reacted to canine blood. Among the 25 samples which were reactive to     human blood, 22 (88,0%) were also reactive to dog. In Araçatuba, L. longipalpis showed eclectic feeding habits           regarding fedding source, showing a high cinophiliac degree. Even though birds did nor represent the major     feeding source, it is important to be alert to their epidemiological meaning, since they allow harboring of the     vector. No feeding changes were observed that could be linked to vector control activities