Man-vector contact of phlebotomine sand flies (Diptera: Psychodidae) in north-central Venezuela as assessed by blood meal identification using dot-ELISA.

Human bait is traditionally used to assess man-vector contact, which is a key point in the study of the epidemiology of vector-borne diseases. However, in highly endemic foci, where this method should be avoided, this information could be obtained by blood meal analysis of engorged insects. In the village El Ingenio, Miranda State, Venezuela, Lutzomyia ovallesi and Lutzomyia gomezi are vectors of cutaneous leishmaniasis (CL). From June 1994 to March 1995, sand flies were collected inside houses on 974 CDC trap nights from 1900 to 0700 h. A total of 7,281 female sand flies were caught: 68.7% of them were identified as L. ovallesi, and 3.3% were identified as L. gomezi. Almost all of the blood-engorged flies (233 of 237) were dissected and identified, and gut contents were examined by dot enzyme-linked immunosorbant assay (dot-ELISA) using antisera against humans and common household animals including the domestic mouse. The Human Blood Index was 0.817 for L. ovallesi. These results suggest that intradomiciliary transmission may occur and account for the cases of CL frequently observed in newborn children in El Ingenio.