Plasmodium falciparum infection rates for some Anopheles spp. from Guinea-Bissau, West Africa.

Michelle R Sanford,Joao Dinis,Gregory C Lanzaro,Amabelia Rodrigues,Catelyn C Nieman,Clare D Marsden,Anthony J Cornel,Yoosook Lee,Sarah Han,Allison M Weakley

doi:10.12688/f1000research.5485.2

Michelle R Sanford, Joao Dinis + Show 8 more

Open Access

https://doi.org/10.12688/f1000research.5485.2

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Abstract

Presence of Plasmodium falciparum circumsporozoite protein (CSP) was detected by enzyme linked immunosorbent assay (ELISA) in a sample of Anopheles gambiae s.s., A. melas and A. pharoensis collected in Guinea-Bissau during October and November 2009. The percentage of P. falciparum infected samples (10.2% overall; confidence interval (CI): 7.45-13.6%) was comparable to earlier studies from other sites in Guinea-Bissau (9.6-12.4%). The majority of the specimens collected were identified as A. gambiae which had an individual infection rate of 12.6 % (CI: 8.88-17.6) across collection sites. A small number of specimens of A. coluzzii, A. coluzzii x A. gambiae hybrids, A. melas and A. pharoensis were collected and had infection rates of 4.3% (CI:0.98-12.4), 4.1% (CI:0.35-14.5), 11.1% (CI:1.86-34.1) and 33.3% (CI:9.25-70.4) respectively. Despite being present in low numbers in indoor collections, the exophilic feeding behaviors of A. melas (N=18) and A. pharoensis (N=6) and high infection rates observed in this survey suggest falciparum-malaria transmission potential outside of the protection of bed nets.

Highlights

Malaria is among the leading causes of childhood mortality in Guinea-Bissau, comprising 18% of mortality of children less than five years of age as of 2010 (WHO, 2010)
Limited research has been conducted on the vectors and malaria parasite infection rates in Guinea-Bissau populations of Anopheles species in general and there is no data on comparative infection rates between A. gambiae and A. coluzzii and members of the A. gambiae complex
Mosquitoes were collected by mouth aspiration from both the island and inland areas of Guinea-Bissau (Figure 1) in 2009 between October and November, which corresponds with the time of year previously observed to have the highest infection rate in Anopheles species (Jaenson et al, 1994)

Summary

Introduction

Malaria is among the leading causes of childhood mortality in Guinea-Bissau, comprising 18% of mortality of children less than five years of age as of 2010 (WHO, 2010). We present much needed data on P. falciparum infection of Anopheles spp. specimens collected from inside and around associated human habitations at eight sites in Guinea-Bissau (Table 1).

Results

Conclusion