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Five years of malaria control in the continental region, Equatorial Guinea

Andrea M Rehman1, Andrea G Mann1, Christopher Schwabe2, Michael R Reddy3, Irina Roncon Gomes2, Michel A Slotman4, Lee Yellott5, Abrahan Matias5, Adalgisa Caccone3, Gloria Nseng Nchama6 and Immo Kleinschmidt1*

Author Affiliations

1 MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK

2 Medical Care Development International (MCDI), New Hampshire Office, 104 Bradford Road, Keene, New Hampshire 03431, USA

3 Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA

4 Department of Entomology, Texas A&M University, College Station, Texas, USA

5 MCDI, Malabo Office, Bioko Island, Equatorial Guinea

6 Ministry of Health and Social Welfare, Malabo, Equatorial Guinea

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Malaria Journal 2013, 12:154  doi:10.1186/1475-2875-12-154

Published: 7 May 2013

Abstract

Background

A successful malaria control programme began in 2004 on Bioko Island, Equatorial Guinea. From 2007, the same multiple malaria interventions, though reduced in scope for funding reasons, were introduced to the four mainland provinces of Equatorial Guinea (the continental region) aiming to recreate Bioko’s success. Two provinces received long-lasting insecticidal nets (LLINs) and two provinces received biannual indoor residual spraying (IRS). Enhanced case management and communications were introduced throughout.

Methods

Estimates of intervention coverage and indicators of malaria transmission for 2007 to 2011 were derived from annual malaria indicator surveys (MIS). Results were complemented by health information system (HIS) and entomological data. The personal protection offered by LLINs and IRS against Plasmodium falciparum infection was estimated with logistic regression.

Results

The estimated proportion of children aged 1–4 using either an LLIN the previous night or living in a house sprayed in the last six months was 23% in 2007 and 42% in 2011. The estimated prevalence of P. falciparum in children aged 1–4 was 68% (N=1,770; 95% confidence interval [CI]: 58-76%) in 2007 and 52% (N=1,602; 95% CI: 44-61%) in 2011. Children 1–4 years had lower prevalence if they used an LLIN the previous night (N=1,124, 56%; adjusted odds ratio [aOR] 0.64, 95% CI: 0.55-0.74) or if they lived in a sprayed house (N=1,150, 57%; aOR 0.80, 95% CI: 0.62-1.03) compared to children with neither intervention (N=4,131, 66%, reference group). The minority of children who both used an LLIN and lived in a sprayed house had the lowest prevalence of infection (N=171, 45%; aOR 0.52, 95% CI: 0.35-0.78). High site-level intervention coverage did not always correlate with lower site-level P. falciparum prevalence. The malaria season peaked in either June or July, not necessarily coinciding with MIS data collection.

Conclusions

Though moderate impact was achieved after five years of vector control, case management, and communications, prevalence remained high due to an inability to sufficiently scale-up coverage with either IRS or LLINs. Both LLINs and IRS provided individual protection, but greater protection was afforded to children who benefitted from both.

Keywords:
Malaria; Equatorial Guinea; Long-lasting insecticide treated bed nets; Indoor residual spraying; Malaria indicator survey