Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, United Kingdom; Environmental Health and Ecological Sciences, Ifakara Health Institute, PO Box 78373, Kiko Avenue, Mikocheni B, Dar es Salaam, Tanzania; Bioelectronics Unit, University of Glasgow, Graham Kerr Building, Glasgow, United Kingdom; Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom; School of Life Sciences, Nelson Mandela African Institute of Science and Technology Tanzania, PO Box 447, Arusha, Tanzania
Maliti, D.V., Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, United Kingdom, Environmental Health and Ecological Sciences, Ifakara Health Institute, PO Box 78373, Kiko Avenue, Mikocheni B, Dar es Salaam, Tanzania, School of Life Sciences, Nelson Mandela African Institute of Science and Technology Tanzania, PO Box 447, Arusha, Tanzania; Govella, N.J., Environmental Health and Ecological Sciences, Ifakara Health Institute, PO Box 78373, Kiko Avenue, Mikocheni B, Dar es Salaam, Tanzania; Killeen, G.F., Environmental Health and Ecological Sciences, Ifakara Health Institute, PO Box 78373, Kiko Avenue, Mikocheni B, Dar es Salaam, Tanzania, Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom; Mirzai, N., Bioelectronics Unit, University of Glasgow, Graham Kerr Building, Glasgow, United Kingdom; Johnson, P.C.D., Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, United Kingdom; Kreppel, K., Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, United Kingdom, Environmental Health and Ecological Sciences, Ifakara Health Institute, PO Box 78373, Kiko Avenue, Mikocheni B, Dar es Salaam, Tanzania; Ferguson, H.M., Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, United Kingdom
Background: The human landing catch (HLC) is the gold standard method for sampling host-seeking malaria vectors. However, the HLC is ethically questionable because it requires exposure of humans to potentially infectious mosquito bites. Methods: Two exposure-free methods for sampling host-seeking mosquitoes were evaluated using electrocuting surfaces as potential replacements for HLC: (1) a previously evaluated, commercially available electrocuting grid (CA-EG) designed for killing flies, and (2) a custom-made mosquito electrocuting trap (MET) designed to kill African malaria vectors. The MET and the CA-EG were evaluated relative to the HLC in a Latin Square experiment conducted in the Kilombero Valley, Tanzania. The sampling consistency of the traps across the night and at varying mosquito densities was investigated. Estimates of the proportion of mosquitoes caught indoors (Pi), proportion of human exposure occurring indoors (πi), and proportion of mosquitoes caught when most people are likely to be indoors (Pfl) were compared for all traps. Results: Whereas the CA-EG performed poorly (<10 % of catch of HLC), sampling efficiency of the MET for sampling Anopheles funestus s.l. was indistinguishable from HLC indoors and outdoors. For Anopheles gambiae s.l., sampling sensitivity of MET was 20.9 % (95 % CI 10.3-42.2) indoors and 58.5 % (95 % CI 32.2-106.2) outdoors relative to HLC. There was no evidence of density-dependent sampling by the MET or CA-EG. Similar estimates of Pi were obtained for An. gambiae s.l. and An. funestus s.l. from all trapping methods. The proportion of mosquitoes caught when people are usually indoors (Pfl) was underestimated by the CA-EG and MET for An. gambiae s.l., but similar to the HLC for An. funestus. Estimates of the proportion of human exposure occurring indoors (πi) obtained from the CA-EG and MET were similar to the HLC for An. gambiae s.l., but overestimated for An. funestus. Conclusions: The MET showed promise as an outdoor sampling tool for malaria vectors where it achieved >50 % sampling sensitivity relative to the HLC. The CA-EG had poor sampling sensitivity outdoors and inside. With further modification, the MET could provide an efficient and safer alternative to the HLC for the surveillance of mosquito vectors outdoors. © 2015 Maliti et al.