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Mapping the receptivity of malaria risk to plan the future of control in Somalia.

Noor AM, Alegana VA, Patil AP, Moloney G, Borle M, Yusuf F, Amran J, Snow RW - BMJ Open (2012)

Bottom Line: Of these, 23% of the districts, home to 13% of the population, were under transmission of <1% PfPR(2-10).About 58% of the districts and 55% of the population were in the risk class of 1% to <5% PfPR(2-10).In contrast, the receptivity map estimated 65% of the districts and 69% of the population were under mesoendemic transmission (>10%-50% PfPR(2-10)) and the rest as hypoendemic.

View Article: PubMed Central - PubMed

Affiliation: Malaria Public Health and Epidemiology Group, Centre for Geographic Medicine Research-Coast, Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya.

ABSTRACT

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 (PfPR(2-10)) and used within a Bayesian space-time geostatistical framework to predict the contemporary (2010) mean PfPR(2-10) and the maximum annual mean PfPR(2-10) (receptive) from the highest predicted PfPR(2-10) 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 PfPR(2-10) map estimated that all districts (n=74) and population (n=8.4 million) in Somalia were under hypoendemic transmission (≤10% PfPR(2-10)). Of these, 23% of the districts, home to 13% of the population, were under transmission of <1% PfPR(2-10). About 58% of the districts and 55% of the population were in the risk class of 1% to <5% PfPR(2-10). In contrast, the receptivity map estimated 65% of the districts and 69% of the population were under mesoendemic transmission (>10%-50% PfPR(2-10)) 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.

No MeSH data available.


Related in: MedlinePlus

Zone, regional and district maps of Somalia showing the distribution of theage-standardised community Plasmodium falciparum parasite rate(PfPR2–10) data (n=1558) assembledduring the period 2007–2010 (including 54 surveys undertaken in 2011).The zones are CS, Central South; NE, North East; NW, North West. The thickblack line show the zone boundaries, the thin black lines show the regionalboundaries and the thin grey lines show the district boundaries. The blueslines show the location of the Juba (lower) and Shabelle (upper) Rivers.
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fig1: Zone, regional and district maps of Somalia showing the distribution of theage-standardised community Plasmodium falciparum parasite rate(PfPR2–10) data (n=1558) assembledduring the period 2007–2010 (including 54 surveys undertaken in 2011).The zones are CS, Central South; NE, North East; NW, North West. The thickblack line show the zone boundaries, the thin black lines show the regionalboundaries and the thin grey lines show the district boundaries. The blueslines show the location of the Juba (lower) and Shabelle (upper) Rivers.

Mentions: Somalia is divided into the three zones of North West (Somaliland), North East(Puntland) and Central South (figure 1). Thenorthern zones are generally dry and hot, whereas the Central South zone hassubtropical climate and is where the two major rivers of the country, the Shabelleand the Juba, are located.1011Anopheles arabiensis is the dominant malaria transmitting vectorthroughout the country, although Anopheles funestus is reported inCentral South.1213P falciparum is the dominant species of the malaria parasite.14–16 The presence ofPlasmodium vivax cases have also been reported with studies inSomaliland showing relatively high vivax antibody responses.17 The failure of the long rains in Somalia in 2010 combined withthe below average rainfalls in previous two seasons have resulted in a severedrought.11


Mapping the receptivity of malaria risk to plan the future of control in Somalia.

Noor AM, Alegana VA, Patil AP, Moloney G, Borle M, Yusuf F, Amran J, Snow RW - BMJ Open (2012)

Zone, regional and district maps of Somalia showing the distribution of theage-standardised community Plasmodium falciparum parasite rate(PfPR2–10) data (n=1558) assembledduring the period 2007–2010 (including 54 surveys undertaken in 2011).The zones are CS, Central South; NE, North East; NW, North West. The thickblack line show the zone boundaries, the thin black lines show the regionalboundaries and the thin grey lines show the district boundaries. The blueslines show the location of the Juba (lower) and Shabelle (upper) Rivers.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4400533&req=5

fig1: Zone, regional and district maps of Somalia showing the distribution of theage-standardised community Plasmodium falciparum parasite rate(PfPR2–10) data (n=1558) assembledduring the period 2007–2010 (including 54 surveys undertaken in 2011).The zones are CS, Central South; NE, North East; NW, North West. The thickblack line show the zone boundaries, the thin black lines show the regionalboundaries and the thin grey lines show the district boundaries. The blueslines show the location of the Juba (lower) and Shabelle (upper) Rivers.
Mentions: Somalia is divided into the three zones of North West (Somaliland), North East(Puntland) and Central South (figure 1). Thenorthern zones are generally dry and hot, whereas the Central South zone hassubtropical climate and is where the two major rivers of the country, the Shabelleand the Juba, are located.1011Anopheles arabiensis is the dominant malaria transmitting vectorthroughout the country, although Anopheles funestus is reported inCentral South.1213P falciparum is the dominant species of the malaria parasite.14–16 The presence ofPlasmodium vivax cases have also been reported with studies inSomaliland showing relatively high vivax antibody responses.17 The failure of the long rains in Somalia in 2010 combined withthe below average rainfalls in previous two seasons have resulted in a severedrought.11

Bottom Line: Of these, 23% of the districts, home to 13% of the population, were under transmission of <1% PfPR(2-10).About 58% of the districts and 55% of the population were in the risk class of 1% to <5% PfPR(2-10).In contrast, the receptivity map estimated 65% of the districts and 69% of the population were under mesoendemic transmission (>10%-50% PfPR(2-10)) and the rest as hypoendemic.

View Article: PubMed Central - PubMed

Affiliation: Malaria Public Health and Epidemiology Group, Centre for Geographic Medicine Research-Coast, Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya.

ABSTRACT

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 (PfPR(2-10)) and used within a Bayesian space-time geostatistical framework to predict the contemporary (2010) mean PfPR(2-10) and the maximum annual mean PfPR(2-10) (receptive) from the highest predicted PfPR(2-10) 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 PfPR(2-10) map estimated that all districts (n=74) and population (n=8.4 million) in Somalia were under hypoendemic transmission (≤10% PfPR(2-10)). Of these, 23% of the districts, home to 13% of the population, were under transmission of <1% PfPR(2-10). About 58% of the districts and 55% of the population were in the risk class of 1% to <5% PfPR(2-10). In contrast, the receptivity map estimated 65% of the districts and 69% of the population were under mesoendemic transmission (>10%-50% PfPR(2-10)) 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.

No MeSH data available.


Related in: MedlinePlus