Lutzomyia longipalpis behavior and control at an urban visceral leishmaniasis focus in Argentina

Abstract

SUMMARYDuring the earlier stages of visceral leishmaniasis transmission in Posadas City, Misiones, both the night activity and attraction to humans of Lutzomyia longipalpis were assessed, in order to provide preliminary recommendations. The impact of peridomestic deltamethrin spraying performed by local officials was also evaluated. Although Lu. longipalpis were found in traps located over a dog the entire night, 90% of the females were captured from 20.30h to 1.30h, and only landed on a human when he was at a distance of 1.5 m from the dog. Peridomestic spraying of deltamethrin (25 mg/m 2 ) reduced the sand fly capture up to seven days post-intervention without dispersion in the border of the sprayed areas. These results support the recommendations about time-space focus of the protection measures: first half of the night, in the backyard, with pets and domestic animals kept at least 5 m from humans. The deltamethrin as it was used did not seem very effective in this scenario; neither did the eventual use of bed nets, at least in adults, due to the place/hour of sand fly higher activity. This study strengthens the need for a multidisciplinary approach to develop prevention strategies based both on biological and anthropological studies.

Lutzomyia longipalpis abundance in the city of Posadas, northeastern Argentina: variations at different spatial scales

“…Because the application of insecticides has not yet shown a long-term effect on vector abundance (Santini et al 2010), there is a need to broaden our knowledge of the natural breeding sites of Lu. longipalpis (Lainson & Rangel 2005).…”

Spatial Distribution of Phlebotominae in Puerto Iguazu-Misiones, Argentina-Brazil-Paraguay Border Area

“…As regards to the minimum temperatures registered, the statistical differences found between sampling days may not be of biological relevance since the maximum temperatures registered exceeded the threshold value proposed for the region (23 °C) 16 . These results suggest that on consecutive sampling days when there are no thermal variations of biological relevance, relative minimum humidity would by itself affect vector abundance and would acquire greater importance.…”

“…In relation to vector control measures, it is important to consider the limited effectiveness of insecticides, which only cover a reduced-range focal spots and act for short periods 16 . Insecticides have no impact unless they are complemented with environmental management measures such as an increase in direct solar radiation on the soil, and a decrease in its humidity and organic matter, as well as the removal or rotation of pets or domestic animals coordinated with actions to control reservoirs.…”

The first record of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) in the State of Paraná, Brazil

“…In Argentina, where more studies on sandflies have been carried out, the geographical distribution of Lu. longipalpis includes several municipalities in the provinces of Corrientes, Entre Rios, Formosa and Misiones [10][11][12] . In Misiones, Lu.…”