Patterns of anopheline feeding/resting behaviour and Plasmodium infections in North Cameroon, 2011\u20132014: implications for malaria control

Wolfgang Eyisap Ekoko,Josiane Etang,Immo Kleinschmidt,Salomon Patchoke,Abraham Mnzava,Jerome Achille Binyang,Tessa Knox,Martin Donelly,Arthur Mbida Mbida,Alain Dongmo,Jean-Claude Toto,Philippe Nwane,Lili Ranaise Mbakop,Stanislas Mandeng,Jude Bigoga,Narcisse Nvondo,Michael Piameu,Etienne Fondjo,Parfait Awono-Ambene

doi:10.1186/s13071-019-3552-2

Abstract

BackgroundEffective malaria control relies on evidence-based interventions. Anopheline behaviour and Plasmodium infections were investigated in North Cameroon, following long-lasting insecticidal net (LLIN) distribution in 2010.MethodsDuring four consecutive years from 2011 to 2014, adult mosquitoes were collected indoors, outdoors and in exit traps across 38 locations in the Garoua, Pitoa and Mayo-Oulo health districts. Anophelines were morphologically and molecularly identified, then analysed for blood meal origins and Plasmodium falciparum circumsporozoite protein (Pf-CSP). Blood from children under 5 years-old using LLINs was examined for Plasmodium infections.ResultsOverall, 9376 anophelines belonging to 14 species/sibling species were recorded. Anopheles gambiae (s.l.) [An. arabiensis (73.3%), An. coluzzii (17.6%) and An. gambiae (s.s.) (9.1%)] was predominant (72%), followed by An. funestus (s.l.) (20.5%) and An. rufipes (6.5%). The recorded blood meals were mainly from humans (28%), cattle (15.6%) and sheep (11.6%) or mixed (45%). Pf-CSP rates were higher indoors (3.2–5.4%) versus outdoors (0.8–2.0%), and increased yearly (χ2 < 18, df = 10, P < 0.03). Malaria prevalence in children under 5 years-old, in households using LLINs was 30% (924/3088).ConclusionsThe present study revealed the variability of malaria vector resting and feeding behaviour, and the persistence of Plasmodium infections regardless the use of LLINs. Supplementary interventions to LLINs are therefore needed to sustain malaria prevention in North Cameroon.

Highlights

Effective malaria control relies on evidence-based interventions
The anopheline fauna was more diverse in the Pitoa health districts (HD) with 12 species recorded, followed by the Garoua HD with 9 species recorded, while only 6 species were identified in samples from the Mayo Oulo HD
While An. coluzzii and An. gambiae were at relatively low proportion across the three HDs (5–12%), An. arabiensis was the predominant species of the entire fauna from the Mayo Oulo and Pitoa HDs (50–58%), followed by An. funestus

Summary

Introduction

Effective malaria control relies on evidence-based interventions. Anopheline behaviour and Plasmodium infections were investigated in North Cameroon, following long-lasting insecticidal net (LLIN) distribution in 2010. The key elements that make these species highly efficient malaria vectors are anthropophagic and anthropophilic behaviour, i.e. a preference for humans as a source of blood, combined with indoor resting habits (endophily), and exploitation of breeding habitats created by human activities [3,4,5]. Knowledge of these vector innate feeding preferences and resting habits when combined with data on host availability/accessibility accurately predicts the intensity of malaria transmission [6]. Mosquitoes that do not enter houses will have a selective survival advantage and the intervention may have little effect, especially if these mosquitoes are opportunistic, resistant to insecticides or exhibit plasticity in host selection

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Conclusion