Mapping the receptivity of malaria risk to plan the future of control in Somalia
- Abdisalan Mohamed Noor1,2,
- Victor Adagi Alegana1,
- Anand Prabhakar Patil3,
- Grainne Moloney4,
- Mohammed Borle4,
- Fahmi Yusuf5,
- Jamal Amran5,
- Robert William Snow1,2
- 1Malaria Public Health and Epidemiology Group, Centre for Geographic Medicine Research-Coast, Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
- 2Nuffield Department of Medicine, John Radcliffe Hospital, Centre for Tropical Medicine, University of Oxford, Headington, Oxford, UK
- 3Sense Inc., Detroit, Michigan, USA
- 4Food Security and Nutrition Analysis Unit-Somalia, United Nations Food and Agricultural Organization, Nairobi, Kenya
- 5World Health Organization, Malaria Control and Elimination, Somalia Office, Nairobi, Kenya
- Correspondence to Dr Abdisalan Mohamed Noor;
- Received 13 March 2012
- Accepted 18 June 2012
- Published 31 July 2012
Objectives To measure the receptive risks of malaria in Somalia and compare decisions on intervention scale-up based on this map and the more widely used contemporary risk maps.
Design Cross-sectional community Plasmodium falciparum parasite rate (PfPR) data for the period 2007–2010 corrected to a standard age range of 2 to <10 years (PfPR2–10) and used within a Bayesian space–time geostatistical framework to predict the contemporary (2010) mean PfPR2–10 and the maximum annual mean PfPR2–10 (receptive) from the highest predicted PfPR2–10 value over the study period as an estimate of receptivity.
Setting Randomly sampled communities in Somalia.
Participants Randomly sampled individuals of all ages.
Main outcome measure Cartographic descriptions of malaria receptivity and contemporary risks in Somalia at the district level.
Results The contemporary annual PfPR2–10 map estimated that all districts (n=74) and population (n=8.4 million) in Somalia were under hypoendemic transmission (≤10% PfPR2–10). Of these, 23% of the districts, home to 13% of the population, were under transmission of <1% PfPR2–10. About 58% of the districts and 55% of the population were in the risk class of 1% to <5% PfPR2–10. In contrast, the receptivity map estimated 65% of the districts and 69% of the population were under mesoendemic transmission (>10%–50% PfPR2–10) and the rest as hypoendemic.
Conclusion Compared with maps of receptive risks, contemporary maps of transmission mask disparities of malaria risk necessary to prioritise and sustain future control. As malaria risk declines across Africa, efforts must be invested in measuring receptivity for efficient control planning.
To cite: Noor AM, Alegana VA, Patil AP, et al. Mapping the receptivity of malaria risk to plan the future of control in Somalia. BMJ Open 2012;2:e001160. doi:10.1136/bmjopen-2012-001160
Contributors AMN was responsible for overall scientific management, study design, data cleaning, analysis, interpretation, drafting and production of the final manuscript. VAA was responsible for data cleaning, geo-coding, analysis and contributed to the final manuscript. APP was responsible for the coding of the MBG framework, developed the supplementary information on model specifications and contributed to final manuscript. GM and MB contributed to the survey design, data assembly and cleaning and contributed to final manuscript. FY and JA contributed to survey design, interpretation of results and contributed to final manuscript. RWS provided scientific guidance and contributed to the analysis, interpretation and preparation of the final manuscript. All authors read and approved the final manuscript.
Funding Cross-sectional survey was funded by the FAO-FSNAU and partners. AMN is supported by the Wellcome Trust as an Intermediate Research Fellow (095127). RWS is supported by the Wellcome Trust as Principal Research Fellow (079080) that also funded support to APP. Programmatic support for this study was also provided through a Wellcome Trust Major Overseas Programme grant to the KEMRI/Wellcome Trust Research Programme (092654).
Competing interests None.
Ethics approval Ethical approval was provided through permission by the Ministry of Health Somalia, Transitional Federal government of Somalia Republic, Ref: MOH/WC/XA/146./07, dated 2 February 2007. Informed verbal consent was sought from all participating households and individuals. Participants who were positive for Plasmodium falciparum infection was treated with the correct dosages of the nationally recommended antimalarials.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data from this study are not in the public domain.
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