Nocturnal activities of phlebotomine sand flies (Diptera: Psychodidae) in Baringo County, Kenya

Abstract

Leishmaniasis is a disease of both humans and animals. It is transmitted by the bite of sand flies of the genus Phlebotomus in the Old World and Lutzomyia in the New World. Nocturnal activities of phlebotomine sand flies were monitored by trapping flies exiting and entering termite mounds and animal burrows in Baringo County. Exit/entrance traps were set from dusk to midnight and from midnight to dawn in the termite mound and animal burrow openings. The study which lasted seven months (November 1993/May 1994), was designed to reveal sand fly behavior in their natural habitats. A total of 11,787 sand flies was trapped and their nocturnal activities studied. Significantly more sand flies(85.6%) were caught exiting than entering animal burrows and termite mounds in the 1^st half of the night p<0.05. This trend was reversed by sand flies (61.4%) caught entering the burrows termite mounds during the 2^nd half of the night p<0.05. Most sugar/positive sand flies were collected after midnight in both animal burrows and termite mounds while more blood/fed sand flies were caught in the 1^st than in the 2nd half of the night p<0.05. At Perkerra, 87.8% of the blood/fed female sand flies were trapped in the 1^st half of the night compared with 12.2% caught in the 2nd half. At Rabai, 72.6% of the total number of those caught blood fed were in the 1^st half and 27.4% in the 2^nd half of the night. P. martini which is the vector of L. donovani which causes visceral leishmaniasis, was predominantly trapped in termite mounds whereas P duboscqi (vector of L. major) that causes cutaneous leishmaniasis, was trapped in large numbers in animal burrows. These habitats pre/dispose themselves as ideal targets for control measures of the vectors.

Keywords: Sugar, blood feeding, sand flies, animal burrows, termite mounds, Kenya