Malaria

Malaria

    Overview

    Malaria is a mosquito-borne infectious disease caused by protozoan parasites belonging to the genus Plasmodium. Five species account for almost all human infections, with P falciparum being the most severe. When an infected mosquito bites a human, it can introduce the parasite from its saliva into the person's blood. The long lifespan and strong human-biting habit of the Anopheles species that carry malaria are the main reasons for the high incidence of malaria in Africa.  Malaria can be prevented by avoiding mosquito bites and with medicines. Treatments can stop mild cases from getting worse.

    Symptoms and treatment

    Malaria symptoms usually start within 10-15 days of getting bitten by an infected mosquito. Getting tested early is important as some types of malaria can cause severe illness and death. Infants, children under 5 years, pregnant women, travellers, and people with HIV or AIDS are at higher risk. Severe symptoms include extreme tiredness and fatigue, impaired consciousness, multiple convulsions, difficulty breathing, dark or bloody urine, jaundice, and abnormal bleeding.

    People with severe symptoms should get emergency care right away. Malaria infection during pregnancy can also cause premature delivery, stillbirth, or delivery of a baby with low birth weight.

    WHO recommends that all suspected cases of malaria be confirmed using parasite-based diagnostic testing. Malaria is a serious infection and requires treatment with multiple medicines. The most common medicines are Artemisinin-based combination therapy medicines like artemether-lumefantrine, artesunate+amodiaquine, artesunate+mefloquine, artesunate+sulfadoxine-pyrimethamine, dihydroartemisinin+piperaquine and artesunate+pyronaridine. Primaquine should be added to the main treatment to prevent relapses of infection with the P. vivax and P. ovale parasites. In case of severe disease, people need to go to a health centre or hospital for injectable medicines.

    WHO Response

    Anopheles stephensi

    Anopheles stephensi is a major threat to the control and elimination of malaria in Africa, but large-scale surveillance of the vector is needed. An stephensi has been expanding its range over the last decade, with detections reported in Djibouti, Ethiopia, Sudan, Somalia, Nigeria and Ghana. It thrives in urban settings. Countries are encouraged to step up surveillance activities to ensure early detection of this vector.

    RTS, S/AS01 (RTS, S) malaria vaccine

    WHO has been leading efforts to introduce the RTS, S vaccine in African countries with high malaria burden. In 2019, the vaccine was introduced in Ghana, Kenya, and Malawi as part of a pilot program to assess its effectiveness and safety in real-world settings. Following the WHO recommendation for broader use of the malaria vaccine in moderate to high Plasmodium falciparum malaria transmission areas, issued in October 2021, the WHO has supported Ghana and Malawi to expand the vaccine administration in comparator areas. By the end of March 2023, 1.5 million children with RTS, S, and more than 4.1 million doses had been administered since the initial launch in 2019. Malawi launched expansion of RTS, S on 29 November 2022. It was followed by Ghana, which launched the expansion on 20 February 2023. Kenya launched the expansion on 7 March 2023.  At least 28 countries in Africa have expressed interest in introducing the vaccine, with some additional countries to start in early 2024. The unprecedented demand for the first malaria vaccine is considered an opportunity to bring children back to clinics to catch up on missed vaccines and child health interventions – including reinforcing the need for children to sleep under ITNs every night. WHO has also been working with African countries to scale up other proven malaria control interventions, such as insecticide-treated bed nets, indoor residual spraying, intermittent preventive treatment of malaria in pregnant women, seasonal malaria chemoprevention, perennial malaria chemoprevention in young children as well as prompt diagnosis and treatment of malaria cases.

    Key fact

    Asset 4

    247 million cases

    of malaria estimated worldwide in 2021 in 84 endemic countries

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    • 619 000 malaria deaths worldwide in 2021
    • 95% (234 million) of malaria cases reported in Africa in 2021
    • 96% of malaria deaths (593.000) reported in Africa in 2021

    Malaria remains a significant public health and development challenge. The African Region shoulders the heaviest malaria burden: with (95% of cases and 96% of deaths globally) with 234 million malaria cases and 593 000 of deaths, 78.9% of deaths were in children aged under five years in 2021

    Challenges

    The biggest challenge faced by malaria endemic countries in Africa is inadequate financing for malaria prevention and treatment services for people at risk of malaria. As a result, there are communities or populations that cannot access prevention measures or treatment when needed. In some parts of sub-Saharan Africa, mosquitoes that transmit malaria have become resistant to certain older insecticides.

    Who is at risk?

    Some people are more vulnerable to malaria than others.  Partial immunity to malaria can be developed over years of exposure.  As young children have not had the opportunity to build up this partial immunity, they are particularly at risk, and make up the majority of fatal cases of malaria in the WHO African Region.

    As well as having a significant human cost, the effects of malaria extend far beyond direct measures of morbidity and mortality.  Malaria can reduce school attendance, productivity at work, and there is evidence that the disease can also impair intellectual development. The economic costs are also significant.  Between 1965 and 1990, countries in which a large proportion of the population lived in regions with malaria experienced an average growth in per-capita GDP of 0.4% per year, whereas average growth in other countries was 2.3% per year.

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    Disease burden

    Disease burden

    Malaria is widespread throughout tropical and subtropical regions of the world, and Africa carries a disproportionately high share of the global malaria burden, both in terms of total malaria cases and malaria deaths. In 2017, there were an estimated 219 million cases of malaria worldwide.  Most were in the WHO African Region, with an estimated 200 million cases, or 92% of global cases.   In 2017, five countries accounted for nearly half of all malaria cases worldwide.  Four of these were in Africa: Nigeria (25%), the Democratic Republic of the Congo (11%), Mozambique (5%), and Uganda (4%).

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    Featured news

    Inching closer to malaria elimination
    Se rapprocher un peu plus de l’élimination du paludisme
    Beyond the numbers: the real-world impact of the malaria vaccine in Kenya
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    Le vaccin antipaludique, une pièce maîtresse dans la lutte contre le paludisme au Ghana
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    Au Malawi, les mères apprécient le premier vaccin contre le paludisme