Reduced human-biting preferences of the African malaria vectors Anopheles arabiensis and Anopheles gambiae in an urban c
- PDF / 1,160,380 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 49 Downloads / 189 Views
Malaria Journal Open Access
RESEARCH
Reduced human‑biting preferences of the African malaria vectors Anopheles arabiensis and Anopheles gambiae in an urban context: controlled, competitive host‑preference experiments in Tanzania Yeromin P. Mlacha1,2,3* , Prosper P. Chaki1,4, Athuman Muhili1, Dennis J. Massue5,6, Marcel Tanner2,3, Silas Majambere4, Gerry F. Killen1,7,8 and Nicodem J. Govella1,9
Abstract Background: Host preference is a critical determinant of human exposure to vector-borne infections and the impact of vector control interventions. Widespread use of long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) across sub-Saharan Africa, which protect humans against mosquitoes, may select for altered host preference traits of malaria vectors over the long term. Here, the host preferences of Anopheles arabiensis and Anopheles gambiae sensu stricto (s.s.) were experimentally assessed in the field, using direct host-preference assays in two distinct ecological settings in Tanzania. Methods: Eight Ifakara Tent Trap (ITT), four baited with humans and four with bovine calves, were simultaneously used to catch malaria vectors in open field sites in urban and rural Tanzania. The numbers of mosquitoes collected in human-baited traps versus calf-baited traps were used to estimate human feeding preference for each site’s vector species. Results: The estimated proportion [95% confidence interval (CI)] of mosquitoes attacking humans rather than cattle was 0.60 [0.40, 0.77] for An. arabiensis in the rural setting and 0.61 [0.32, 0.85] for An. gambiae s.s. in the urban setting, indicating no preference for either host in both cases (P = 0.32 and 0.46, respectively) and no difference in preference between the two (Odds Ratio (OR) [95%] = 0.95 [0.30, 3.01], P = 0.924). However, only a quarter of An. arabiensis in the urban setting attacked humans (0.25 [0.09, 0.53]), indicating a preference for cattle that approached significance (P = 0.08). Indeed, urban An. arabiensis were less likely to attack humans rather than cattle when compared to the same species in the rural setting (OR [95%] = 0.21 [0.05, 0.91], P = 0.037). Conclusion: Urban An. arabiensis had a stronger preference for cattle than the rural population and urban An. gambiae s.s. showed no clear preference for either humans or cattle. In the urban setting, both species exhibited stronger tendencies to attack cattle than previous studies of the same species in rural contexts. Cattle keeping may, therefore,
*Correspondence: [email protected]; [email protected] 1 Ecological Sciences Department, Ifakara Health Institute, Environmental Health, Kiko Avenue, P.O. Box 78373, Mikocheni, Dar es Salaam, United Republic of Tanzania Full list of author information is available at the end of the article © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriat
Data Loading...
