BIOLOGY OF PHLEBOTOMUS SANDFLIES (DIPTERA, PSYCHODIDAE) IN 2 CONTRASTING LEISHMANIASIS FOCI OF SOUTH-WEST SAUDI-ARABIA

In south-west Saudi Arabia two forms of leishmaniasis occur. Visceral disease (VL) due to Leishmania infantum affects humans (mainly infants ) in lowland areas and cutaneous disease (CL) due to L. tropica affect s a broader age group in highland areas. Leishmania infantum is common in dogs and may occasionally infect man. Longitudinal sampling of san dflies in two foci with matched sticky and light traps inside and outs ide houses demonstrated that, although the species composition was ver y similar, the dominant species in the highlands (Phlebotomus sergenti Parrot) was different from that in the lowlands (P. bergeroti Parrot) . Ln both habitats there was a marked seasonal variation in abundance, peak levels in the lowlands preceding the highlands, as did sandfly n umbers inside houses compared to outside houses. Phlebotomus sergenti were found infected with L. tropica in June and July which, together w ith its endophilic behaviour, incriminated this species as the vector of cutaneous disease. The vector of visceral disease in humans is susp ected to be either P. alexandri Sinton or P. orientalis Parrot, but no t P. arabicus Theodor as previously suggested.