Malaria Vector Bionomics During the Dry Season in Nchelenge District, Zambia

Smita Das and Douglas E Norris of the Johns Hopkins Bloomberg School of Public Health Department of Molecular Microbiology and Immunology and Johns Hopkins Malaria Research Institute have written our guest blog posting based on a poster they presented at the recent JHU Global Health Day.

picture1-smita-das-and-douglas-norris-jhmri-sm.jpgAs part of the International Centers of Excellence in Malaria Research (ICEMR) in Southern Africa project, mosquito collections are being conducted in Nchelenge District in Luapula Province, Zambia. Nchelenge experiences hyperendemic malaria despite continued implementation of indoor residual spraying (IRS) and long-lasting insecticide nets (LLINs) as control measures.

Center for Disease Control light trap (CDC LT) and pyrethroid spray catch (PSC) collections performed during the wet season in April 2012 revealed the presence of both Anopheles gambiae s.s. and An. funestus s.s. Both species were highly anthropophilic and the Plasmodium falciparum sporozoite infection rate in An. funestus was higher compared to An. gambiae.

In the dry season collections, An. funestus continued to be the dominant species with even fewer An. gambiae caught compared to the wet season.  Due to the abundance of An. funestus and high human malaria infection rates in Nchelenge, it is predicted that the human blood index and entomological inoculation rate for An. funestus is higher than that of An. gambiae in both seasons.

The multiple blood feeding behavior and insecticide resistance status of both malaria vectors will also be explored as this can give us an idea of estimating the transmission potential of these mosquitoes. The vector data in Nchelenge present unique opportunities to further our understanding of malaria transmission and the implications for malaria control in high-risk areas.

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