Detection of Anopheles rivulorum-like, a member of the Anopheles funestus group, in South Africa

Abstract

BACKGROUND : The Anopheles gambiae sensu lato (s.l.) and Anopheles funestus s.l. species complexes contain the most important malaria vectors in Africa. Within the An. funestus group of at least 11 African species, the vector status of all but the nominal species An. funestus appears poorly investigated, although evidence exists that Anopheles rivulorum and Anopheles vaneedeni may play minor roles. A new species, An. rivulorum-like, was described from Burkina Faso in 2000 and subsequently also found in Cameroon and Zambia. This is the first paper reporting the presence of this species in South Africa, thereby significantly extending its known range. METHODS : Mosquitoes were collected using dry-ice baited net traps and CDC light traps in the Kruger National Park, South Africa. Sixty-four An. funestus s.l. among an overall 844 mosquitoes were captured and identified to species level using the polymerase chain reaction assay. All samples were also analysed for the presence of Plasmodium falciparum circumsporozoite protein using the enzyme-linked-immunosorbent assay. RESULTS : Four members of the An. funestus group were identified: An. rivulorum-like (n = 49), An. rivulorum (n = 11), Anopheles parensis (n = 2) and Anopheles leesoni (n = 1). One mosquito could not be identified. No evidence of P. falciparum was detected in any of the specimens. CONCLUSION : This is the first report of An. rivulorum-like south of Zambia, and essentially extends the range of this species from West Africa down to South Africa. Given the continental-scale drive towards malaria elimination and the challenges faced by countries in the elimination phase to understand and resolve residual transmission, efforts should be directed towards determining the largely unknown malaria vector potential of members of the An. funestus group and other potential secondary vectors.