Abundance of Lutzomyia ovallesi but not Lu. gomezi (Diptera: Psychodidae) correlated with cutaneous leishmaniasis incidence in north-central Venezuela.

FELICIANGELI, M. D. AND J. RABINOVICH

MEDICAL AND VETERINARY ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 1998 p. 121 - 131

0269-283X

In north-central Venezuela Lutzomyia gomezi and Lu. ovallesi are the main endophiliclanthropophilic species of phlebotomine sandflies implicated as vectors of cutaneous leishmaniasis (CL). Lutzomyia ovallesi has been found infected with Leishmania braziliensis (1.2%) and less often with Le. mexicana (0.07%), while Le. braziliensis infections have also been found in Lu. gomezi (0.47%). We investigated population densities of these sandflies using two sampling mcthods with four series of collections between January 1991 and March 1995 at El Ingenio, Miranda State. All-night outdoor collections from a Shannon trap were correlated with indoor collections from CDC light-traps by linear regression, which proved to be statistically significant for both species. Estimated numbers of female sandflies per house per night were found to be proportional to monthly precipitation (i.e. rainfall), with a lag time of seven months for Lu. ovallesi and of six months for Lu. gomezi. Predominance of Lu. ovallesi over Lu. gomezi (c. 10 :I ) was observed throughout the year, with the number of infected females estimated as 0.043 f_ 0.047 Lu. ovallesi and 0.0085 ? 0.0124 Lu. gomezi per CDC trap per house per night (ratio - 5:l). The mean rate of new CL cases per house per year and sandfly abundance were correlated by linear regression, showing a statistically significant relationship for Lu. ovallesi but not for Lu. gomezi. The negative intercept indicated that, on average, the CDC trap density exceeds 800 Lu. ovallesi femaleshouselyear before new CL cases occur at El Ingenio. Key words. L