Paludisme (Sources: World Malaria Report 2009/2010 - Annex; Africa Malaria Country Profiles 2010)
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The greatest disease burden from malaria occurs in the WHO African Region, where 89% of all malaria deaths worldwide took place in 2008. Over the past 20 years, malaria has been rising in importance on the public health agenda, following a number of high-level measures at national and international level.
The most commonly used intervention policies and strategies for prevention and treatment include use of:
- insecticide-treated nets for vector control
- indoor residual spraying
- intermittent preventive treatment of malaria in pregnancy
- artemisinin-based combination therapy.
While use of insecticide-treated mosquito nets is cost effective and uptake is increasing, use by children and pregnant women is less than the 80% target established by the World Health Assembly.
Indoor residual spraying has increased rapidly since 2005, protecting up to 59 million people in 20 countries. Twenty countries are now implementing malaria control and intermittent preventive treatment in pregnancy on a countrywide basis, and artemisinin-based control therapy has been identified as the treatment of choice in 42 of 43 countries.
However, despite advances in procuring this treatment, only 16% of children with malaria are to date treated with it. Use of artemisinin monotherapy continues, with risks of emerging resistance to artemisinin combination therapy. Overdiagnosis and overtreatment are long-term problems, with up to 96% of febrile patients receiving malaria treatment without parasitological diagnosis.
Financial flow to address malaria control has greatly increased due to the higher international profile of the disease. However, better surveillance and reporting are needed to reduce reliance on estimates from modelling and to track effectiveness of interventions.
Of all WHO regions, the African Region is most severely affected by malaria. It accounted for 85% of the estimated 243 million malaria episodes and 89% of the malaria deaths worldwide in 2008. On average, malaria accounts for 25%–45% of all outpatient clinic attendance, and between 20% and 45% of all hospital admissions. Furthermore, it is estimated that malaria represents 17% of the mortality rate of children aged under 5 years in the Region.
Intervention policies and strategies
The key malaria interventions comprise:
- vector control using insecticide-treated nets
- indoor residual spraying
- intermittent preventive treatment of malaria in pregnancy
- effective treatment using WHO-recommended artemisinin-based combination therapy.
Implemented at country level, these interventions are supported by global, regional, national and subnational partnerships.
Implementing malaria control
Since 1991, various initiatives, resolutions and meetings have placed malaria at the top of the public health agenda. In 1998, the Roll Back Malaria Initiative was launched to advocate for and coordinate malaria control efforts, with the aim of halving the malaria burden by 2010. The Roll Back Malaria Initiative generated increased commitment to malaria prevention and control, culminating in the African Union Heads of State call in Abuja in 2006 for universal access to HIV/AIDS, tuberculosis and malaria services by 2010, and the call for malaria elimination. This was followed by the UN Secretary-General’s call for 100% malaria control coverage by 2010.
Insecticide-treated nets (ITNs) are among the most cost-effective malaria control interventions. Most ITNs are available on a free or subsidized basis, whereby distribution is frequently linked to antenatal care services, routine immunization services or integrated child survival campaigns. Between 2006 and 2009, over 170 million nets had been distributed in the WHO African Region – sufficient to protect 48% of the population at risk of malaria, on the assumption that one net covers two people.
Data from recent surveys indicate that ITN use has increased across the Region. It is estimated that in 2008, 30% of households owned at least one ITN. However, household ownership was shown to exceed 60% in Equatorial Guinea, Ethiopia, Gabon, Mali, Sao Tome and Principe, Senegal and Zambia. Use of ITNs by children aged under 5 years was estimated at 24%. ITN use by pregnant women is similar to that of children aged under 5 years. However, the percentage of children and pregnant women using nets remains significantly below the 80% target identified by the World Health Assembly.
Historically, indoor residual spraying has mostly been deployed in countries with low or unstable transmission of malaria in southern Africa. Since 2005, indoor residual spraying has been deployed progressively in over 20 countries of the Region. The number of people protected by indoor residual spraying more than doubled between 2006 and 2008, rising from 15 million to 59 million. This represented about 9% of the population at risk of malaria in the WHO African Region in 2008. Countries that were able to protect more than 15% of the population at risk in 2008 included Botswana (38%), Equatorial Guinea (56%), Ethiopia (51%), Madagascar (32%), Mozambique (30%), Namibia (16%) and Zambia (47%).
By the end of 2007, intermittent preventive treatment during pregnancy had been adopted in all the 35 endemic countries for which this strategy was recommended, and 20 countries were implementing it countrywide. In 2007–2008, the estimated percentage of women who received two doses of intermittent preventive treatment during pregnancy was 20%, ranging from 3% in Angola to 66% in Zambia.
Artemisinin-based combination therapy (ACT) is now the treatment of choice in 42 of the 43 malaria-endemic countries. Of these, 20 countries are implementing ACTs countrywide. The number of ACT treatment courses procured per year has increased markedly, rising from 31 million doses in 2005 to 160 million doses in 2009. Data from 13 surveys conducted in 2007–2008 show that although on average 32% of children with fever received antimalarial treatment, only 16% were treated with ACT. Moreover, less than 60% of these treatments were obtained from health facilities.
Only Tanzania (22%) and Gabon (25%) exceeded 15% for ACT treatment, with most countries registering less than 5%. As with ITN use, this is well below the World Health Assembly target of 80%. The continued use of artemisinin monotherapy, particularly in the private sector, remains a major setback, potentially contributing to the emergence of resistance and to shortening the useful therapeutic life of ACT.
Malaria treatment is still characterized by gross overdiagnosis and overtreatment. Studies have shown that between 32% and 96% of febrile patients receive antimalarial treatment without parasitological diagnosis. In some cases it has been shown that only 30% of febrile patients receiving ACT are proven to have malaria. Such improper diagnostic practices undermine the correct management of both malaria and fevers due to other causes.
Although progress has been made in malaria control by most countries, none has attained the internationally agreed targets of universal access to essential prevention and control interventions.
Financing malaria control
International funding commitments for malaria control have increased from approximately US $ 0.3 billion in 2003 to US $ 1.7 billion in 2009. This increase is largely due to the emergence of the Global Fund to Fight AIDS, TB and Malaria, and greater commitments by governments, the President’s Malaria Initiative, The World Bank and other stakeholders. This increase in funding has resulted in a dramatic scaling-up of malaria control interventions in many settings, with measurable reductions in the malaria burden.
State of surveillance
Robust surveillance, monitoring and evaluation systems are essential if countries are to assess progress in combating malaria. Countries in the WHO African Region depend on health management information systems and integrated disease surveillance and response for reporting malaria morbidity and mortality. Household surveys provide data on malaria control intervention coverage.
These systems are still weak in most countries, with the result that reporting is incomplete. Assessment of the impact of malaria control interventions is therefore estimated on the basis of modelling techniques. In addition, not all countries of the Region conduct surveys at the same time. Consequently, coverage estimates are made based on data collected during the same time period.
Impact of malaria control interventions
Rapid impact in malaria control, shown in declining morbidity and mortality figures, is possible where a comprehensive package of malaria prevention and control interventions is implemented at the same time. In some countries that have achieved high coverage with insecticide-treated nets and treatment programmes, recorded cases and deaths due to malaria have fallen by 50%. These include Botswana, Eritrea, Ethiopia, Kenya, Rwanda, South Africa, Sao Tome and Principe, Swaziland, Zanzibar (in United Republic of Tanzania) and Zambia.
Endnotes: sources, methods, abbreviations, etc.
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Liste des tableaux / figures
Atlas Figure 74: cas notifiés de paludisme, en 1000, dans la Région africaine, par pays, 2008. Atlas Figure 77: Proportion d'enfants de moins de 5 ans avec fièvre traités avec des médicaments antipaludiques dans la Région africaine, par pays, 2005-2009 et 2000-2004.
Références (ouvrages consultés)
World Malaria Report 2009 http://www.who.int/malaria/publications/atoz/9789241563901/en/index.html
Journée mondiale contre le paludisme en Afrique 2010 mise à jour http://rbm.who.int/ProgressImpactSeries/docs/wmd2010report-en.pdf
Financement du paludisme et l'utilisation des ressources: la première décennie de la GAR (RBM 2010)