Resumen

ALVAREZ, Leslie et al. Lethal concentrations (CL₅₀ & CL₉₅) and diagnostic doses of phenitrothion and lambdacyhalothrin on Lutzomyia evansi from Los Pajones, Trujillo State, Venezuela. Bol Mal Salud Amb [online]. 2006, vol.46, n.1, pp.31-37. ISSN 1690-4648.

Lutzomyia evansi is considered an alternative vector of the American visceral Leishmaniasis (AVL) in some localities of Colombia and Venezuela. In Trujillo State, Venezuela, studies on the bionomics of this species revealed that it is associated with the main foci of AVL, with a natural infection rate of 0.23% and is anthropophylic with intradomiciliary and peridomiciliary behavior. Such aspects led us to investigate, under experimental conditions, the response of a wild population of this species against lambdacyhalothrin and phenitrothion, and to assess the lethal concentrations 50 and 95 (LC₅₀ & LC₉₅) and diagnostic doses. L. evansi was captured with Shannon trap in the locality of Los Pajones, Trujillo State, given the fact that this village has not been under insecticide pressure. Bioassays were done by 1-h insect exposure to impregnated papers at different concentrations. Mortality was recorded after 24 h. LC₅₀ and LC₉₅ with phenitrothion were 0.012% and 0.05%, respectively and for lambdacyhalothrin, LC₅₀ was 0.0004% and LC₉₅ 0.0017%, and diagnostic doses were 0.189% for phenitrothion and 0.0063% lambdacyhalothrin. These results are useful for establishing comparisons with other populations of L. evansi in endemic areas for  AVL under a strong pressure of insecticides, and thus determine the concentrations that might reduce the vector population and interrupt disease transmission.

Palabras clave : Lutzomyia evansi; control; insecticides; Leishmaniasis.