Blood feeding behaviour comparison and contribution of Anopheles coluzzii and Anopheles gambiae, two sibling species living in sympatry, to malaria transmission in Alibori and Donga region, northern Benin, West Africa

Abstract

BackgroundThe main goal of this study was to assess the blood feeding behaviour and the contribution Anopheles coluzzii and Anopheles gambiae, 2 sibling species of An. gambiae sensu stricto. present and living in sympatry in 2 regions of northern Benin targeted for indoor residual spraying (IRS).MethodsThe study was carried out in 6 districts of 2 regions of Benin (Alibori and Donga). Human landing catches (HLC) performed inside and outside of the households and pyrethrum spray captures (PSC) carried out in bedrooms were used to sample vector populations (An. gambiae and An. coluzzii). Collected mosquitoes were analysed to estimate the human biting rate indoors and outdoors, the circumsporozoite antigen positivity, and the anthropophagic index using ELISA methodology. Polymerase chain reaction was used to estimate the frequency of the knockdown resistance (kdr) L1014F and the ace-1 mutations, 2 markers associated respectively with pyrethroids and carbamate/organophosphate insecticide resistance.ResultsA higher blood feeding rate was observed in An. gambiae compared to An. coluzzii as well as, a non-pronounced outdoor biting behavior in both species. The latter showed similar anthropophagic and sporozoite rates. However the analysis indicates a seasonal difference in the contribution of each species to malaria transmission associated with shifts in resting behaviour. Anopheles coluzzii females accounted for most of the detected infections: 86% in Alibori and 79% in Donga, during the dry season versus 14.4% and 21.2%, respectively for An. gambiae during the same period. This relationship was reversed in Donga during the rainy season (66% for An. gambiae against 34% for An. coluzzii). Results also indicated lower frequencies of kdr L1014F and ace-1 in An. coluzzii versus An. gambiae.ConclusionDespite similarity in some parameters related to malaria transmission in both surveyed species, An. coluzzii is potentially a more important malaria vector because of high density in the region. It is also characterized by lower frequencies of the ace-1 mutation than is An. gambiae. The ongoing use of pirimiphos methyl (organophosphate) for IRS should continue to show a good impact in Alibori and Donga because of the very low level of the ace-1 mutation in both species.

Behavioural plasticity of Anopheles coluzzii and Anopheles arabiensis undermines LLIN community protective effect in a Sudanese-savannah village in Burkina Faso

“…Indeed, the fraction of bednet-protected people (about two third of the whole population [28]) are likely exposed to mosquito-bites in early evening and early morning, when not sleeping under the LLIN, and receive much less infective bites than estimated in the present study. However, the high biting rates observed between 9 and 10 PM [68] and Bioko island [69]). Although most studies focusing on resting mosquitoes indirectly suggest high endophagy for An.…”

Assessment of the relationship between gametocyte density, multiplicity of infection and mosquito infectivity in Plasmodium falciparum infections

“…gambiae was reported to have a higher blood-feeding rate compared to An. Coluzzii [42]. This finding will help in assessing the infectious reservoirs in different malaria endemic regions thereby guiding the implementation of targeted malaria control interventions.…”

Behavioural plasticity of Anopheles coluzzii and Anopheles arabiensis undermines LLIN community protective effect in a Sudanese-savannah village in Burkina Faso

“…Indeed, the fraction of bednet-protected people (about two third of the whole population [27]) are likely exposed to mosquito-bites in early evening and early morning, when not sleeping under the LLIN, and receive much less infective bites than estimated in the present study. However, the high biting rates Benin [64] and Bioko island [65]). Although studies focusing on resting mosquitoes apparently suggest high endophagy for An.…”