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. 2011 Jul 25:10:203.
doi: 10.1186/1475-2875-10-203.

Changing patterns of malaria during 1996-2010 in an area of moderate transmission in southern Senegal

Philippe Brasseur  1 , Malick Badiane, Moustafa Cisse, Patrice Agnamey, Michel T Vaillant, Piero L Olliaro
Affiliations

Changing patterns of malaria during 1996-2010 in an area of moderate transmission in southern Senegal

Philippe Brasseur et al. Malar J. .

Abstract

Background: Malaria is reportedly receding in different epidemiological settings, but local long-term surveys are limited. At Mlomp dispensary in south-western Senegal, an area of moderate malaria transmission, year-round, clinically-suspected malaria was treated with monotherapy as per WHO and national policy in the 1990s. Since 2000, there has been a staggered deployment of artesunate-amodiaquine after parasitological confirmation; this was adopted nationally in 2006.

Methods: Data were extracted from clinic registers for the period between January 1996 and December 2010, analysed and modelled.

Results: Over the 15-year study period, the risk of malaria decreased about 32-times (from 0.4 to 0.012 episodes person-year), while anti-malarial treatments decreased 13-times (from 0.9 to 0.07 treatments person-year) and consultations for fever decreased 3-times (from 1.8 to 0.6 visits person-year). This was paralleled by changes in the age profile of malaria patients so that the risk of malaria is now almost uniformly distributed throughout life, while in the past malaria used to concern more children below 16 years of age.

Conclusions: This study provides direct evidence of malaria risk receding between 1996-2010 and becoming equal throughout life where transmission used to be moderate. Infection rates are no longer enough to sustain immunity. Temporally, this coincides with deploying artemisinin combinations on parasitological confirmation, but other contributing causes are unclear.

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Figures

Figure 1
Figure 1
Monthly records of consultations for fever, anti-malarial treatments dispensed (on either clinical or parasitological grounds) and projected real (parasitologically-confirmed) malaria cases in Mlomp during 1996-2010.
Figure 2
Figure 2
Relative Risk (RR) of consulting for fever, receiving a malaria treatment and having a parasitologically-proven malaria attack expressed in person-year relative to 1996.
Figure 3
Figure 3
Anti-malarial treatments dispensed at the Mlomp out-patient clinic.
Figure 4
Figure 4
Proportion parasitologically-positive malaria cases by age classes per year over the period 1996-2009.
Figure 5
Figure 5
Mean age of subjects with negative and positive parasitological tests during 1996-2009.
Figure 6
Figure 6
Relative Risk (RR) of a positive or negative parasitological test by using the positive test as reference (blue line) or the year 1996 (red and green lines for negative and positive tests respectively) in the negative binomial model of counts of parasitological tests.
Figure 7
Figure 7
Relative Risk (RR) for a positive parasitological test by using the 0-5y age category as reference in the negative binomial model of counts of parasitological tests.
Figure 8
Figure 8
Average yearly rain falls in Mlomp for the period 1996-2010.
See this image and copyright information in PMC

References

    1. Roll Back Malaria. The Global Malaria Action Plan. Organization WH. Geneva: World Health Organization; 2008.
    1. Byass P. Making sense of long-term changes in malaria. Lancet. 2008;372(9649):1523–1525. doi: 10.1016/S0140-6736(08)61631-1. - DOI - PubMed
    1. Ceesay SJ, Casals-Pascual C, Erskine J, Anya SE, Duah NO, Fulford AJ, Sesay SS, Abubakar I, Dunyo S, Sey O. et al. Changes in malaria indices between 1999 and 2007 in The Gambia: a retrospective analysis. Lancet. 2008;372(9649):1545–1554. doi: 10.1016/S0140-6736(08)61654-2. - DOI - PMC - PubMed
    1. O'Meara WP, Bejon P, Mwangi TW, Okiro EA, Peshu N, Snow RW, Newton CR, Marsh K. Effect of a fall in malaria transmission on morbidity and mortality in Kilifi, Kenya. Lancet. 2008;372(9649):1555–1562. doi: 10.1016/S0140-6736(08)61655-4. - DOI - PMC - PubMed
    1. World Health Organization. World Malaria Report PRESS W. Geneva: World Health Organization; 2009.

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