Comparative evaluation of methods used for sampling malaria vectors in the Kilombero valley, south eastern Tanzania

Abstract

To monitor malaria transmission, effective sampling methods for host seeking vectors are necessary. The suitability of these methods can be determined by field measurements of their trapping efficiencies. We compared the efficiencies of the Human Landing Catch (HLC), the Centers for Disease Control light trap (CDC-LT) placed next to occupied bednets and the Mbita trap for sampling Anopheles gambiae s.l and Anopheles funestus. The sampling methods were rotated through three houses, each with a human bait, for 8 cycles in a 3 x 3 Latin-square design. Relative to the HLC, the efficiency (and 95% c. i) of the CDC-LT for sampling An. gambiae s.l. was 0.331 (0.237 - 0.460) while that for Mbita trap was 0.031 (0.013 - 0.077). For An. funestus however, the sampling efficiencies were 0.818 (0.611 - 1.096) and 0.022 (0.003-0.165) respectively. We conclude that both the CDC-LT placed next to an occupied bednet and the Mbita trap are less efficient than HLC, the latter being evidently unsuitable for use in the Kilombero Valley