Studies on the behaviour and control of phlebotomine sandflies using experimental houses

Programmes for the control of phlebotomine sandflies (Diptera: Psychodidae), the vectors of leishmaniases, mainly target adults because larval breeding sites are generally unknown or inaccessible. To determine how blood-questing sandfly females enter homes and to develop means for their control, an experimental house (EH) was constructed in a village endemic for cutaneous leishmaniasis. Initially, carbon dioxide (CO₂)-baited suction traps were installed inside the EH to attract and capture sandflies. For other experiments, the windows of the EH were fitted with CO₂-baited window entrance traps (WETs) that allow each window to be considered as a separate unit. The majority of captures inside the EH and in WETs consisted of Phlebotomus sergenti, a species that enters inhabited houses relatively infrequently. Analyses of collections in WETs and in sticky traps on external walls showed that sandflies entered windows having landed previously on the wall below or either side of the window. Shelves constructed below windows significantly reduced the numbers of sandflies that entered both the EH and inhabited houses. The lining of internal walls with insecticide-impregnated fabric significantly increased mortality rates of sandflies captured inside the EH. To reduce the biting burden imposed by phlebotomine sandflies, several control measures must be integrated and sustained.