Abstract
BackgroundAnopheles funestus is a major vector of malaria in sub-Saharan Africa. However, because it is difficult to colonize, research on this mosquito species has lagged behind other vectors, particularly the understanding of its susceptibility and interactions with the Plasmodium parasite. The present study reports one of the first experimental infections of progeny from wild-caught An. funestus with the P. falciparum parasite providing a realistic avenue for the characterisation of immune responses associated with this infection.MethodsWild-fed resting An. funestus females were collected using electric aspirators and kept in cages for four days until they were fully gravid and ready to oviposit. The resulting eggs were reared to adults F1 mosquitoes under insectary conditions. Three to five day-old An. funestus F1 females were fed with infected blood taken from gametocyte carriers using an artificial glass-parafilm feeding system. Feeding rate was recorded and fed mosquitoes were dissected at day 7 to count oocysts in midguts. Parallel experiments were performed with the known Plasmodium-susceptible An. coluzzii Ngousso laboratory strain, to monitor our blood handling procedures and infectivity of gametocytes.ResultsThe results revealed that An. funestus displays high and similar level of susceptibility to Plasmodium infection compared to An. coluzzii, and suggest that our methodology produces robust feeding and infection rates in wild An. funestus progeny. The prevalence of infection in An. funestus mosquitoes was 38.52 % (range 6.25–100 %) and the median oocyst number was 12.5 (range 1–139). In parallel, the prevalence in An. coluzzii was 39.92 % (range 6.85–97.5 %), while the median oocyst number was 32.1 (range 1–351).ConclusionsOverall, our observations are in line with the fact that both species are readily infected with P. falciparum, the most common and dangerous malaria parasite in sub-Saharan Africa, and since An. funestus is widespread throughout Africa, malaria vector control research and implementation needs to seriously address this vector species too. Additionally, the present work indicates that it is feasible to generate large number of wild F1 infected An. funestus mosquitoes using membrane feeding assays, which can be used for comprehensive study of interactions with the Plasmodium parasite.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1626-y) contains supplementary material, which is available to authorized users.
Highlights
Anopheles funestus is a major vector of malaria in sub-Saharan Africa
This paper reports the first experiments in which first generation of wild-caught An. funestus mosquitoes are infected with natural P. falciparum gametocytes using an artificial blood feeding system
Mosquito collections Anopheles funestus mosquitoes were collected in Mebelong (6°46′N, 11°70′E), a village situated in humid savannah region, about 350 km North of Yaoundé, the capital city of Cameroon
Summary
Anopheles funestus is a major vector of malaria in sub-Saharan Africa. because it is difficult to colonize, research on this mosquito species has lagged behind other vectors, the understanding of its susceptibility and interactions with the Plasmodium parasite. In sub-Saharan Africa, where about 90 % of all malaria deaths occur, mosquitoes from Anopheles gambiae complex and Anopheles funestus group are the most efficient vectors [2,3,4,5], while P. falciparum is the most common and dangerous parasite responsible for most cases of severe malaria [1]. One of the approaches being pursued is the genetic replacement of vector populations with non-vectors in order to disrupt parasite transmission [9,10,11] This requires first of all a good understanding of the complex and specific interactions between the Plasmodium parasites and its Anopheles vectors, notably the associated immune response
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