Malaria

Malaria

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219 million cases of malaria

worldwide were estimated in 2017.

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92% of global malaria cases

were in the WHO African Region–an estimated 200 million cases.

    Overview

    Malaria is a mosquito-borne infectious disease that affects humans, caused by protozoan parasites belonging to the genus Plasmodium.  Four species account for almost all human infections but the species P falciparum causes the majority of infections in Africa and is responsible for the most severe forms of the disease, with the highest mortality rate. When an infected mosquito bites a human therefore, it can introduce the parasite from its saliva into the person’s blood.  Many different species of mosquito transmit malaria in this way. Each of the malaria-transmitting mosquito species has different lengths of life-cycle, preferred aquatic habitat, and preferred feeding. The long lifespan and strong human-biting habit of the African species that carry malaria are the main reasons for the high incidence of malaria in Africa. Despite the fact it is easily preventable and treatable, malaria continues to have a devastating impact on people’s health and livelihoods around the world.

    Symptoms and treatment

    Symptoms manifest between eight and 25 days after infection, and are typically flu-like: they include headaches, fever, shivering, joint pain, vomiting, jaundice, retinal damage and convulsions.  Paroxysm – feeling suddenly cold and uncontrollable shivering followed by fever and sweating – is extremely common.

    People with severe malaria – usually caused by P. falciparum – display symptoms such as abnormal posture, inability to turn the eyes in the same direction, seizures, or even falling into a coma.  If malaria is not treated quickly, it can progress to severe illness, often leading to multiple organ failure in adults, or even death. Malaria in pregnant women can cause stillbirths, infant mortality, and low birth weight.

    The best way to fight malaria is to prevent infection in the first place.  WHO recommends that all people living in malaria transmission areas practise protection against malaria. Two common methods are: using insecticide-treated mosquito nets and indoor spraying.  By forming a physical barrier between mosquitos and humans, nets are a simple and effective means of preventing infection, particularly if people sleep underneath one, as mosquitos emerge to feed at dawn and dusk.  More people in Africa are benefiting from insecticide-treated nets.  Today, more than half of people at risk from malaria sleep under these nets, whereas in 2010 only 29% of those at risk did so.

    Fumigating homes on an annual or semi-annual basis can also rapidly reduce malaria transmission.  However, this method is not widely used in many sub-Saharan countries.  This is because mosquitos are increasingly resistant to earlier, less expensive forms of insecticide, and for some people, the newer, more effective forms are prohibitively expensive.

    Medicines can also be used for the prevention of malaria, especially for particularly at-risk population groups.  These at-risk groups include young children, pregnant women, and travellers from malaria-free parts of the world who might not have built up any residual immunity.  WHO recommends that pregnant women in areas of Africa with moderate and high malaria transmission rates take an anti-malarial medicine like sulfadoxine-pyrimethamine.  More vulnerable people are receiving this potentially life-saving treatment in Africa each year.  Across the 33 African countries which had been carrying out this treatment, an estimated 22% of eligible pregnant women received the recommended three or more doses, compared with 17% in 2015 and 0% in 2010.

    Malaria can also be prevented by using seasonal malaria chemoprevention.  In 2017, a total of 15.7 million children in 12 countries in Africa’s Sahel region were protected through seasonal malaria chemoprevention (SMC) programmes.  However, about 13.6 million children who could have benefited from this intervention were not covered, mainly due to lack of funding.    

    When malaria infection does occur, it is important that it be quickly diagnosed and treated.  This means that a mild case can be stopped from developing into something more dangerous, even fatal, and it can also prevent malaria from spreading further.  WHO recommends taking four key steps for the effective diagnosis and treatment of malaria:

    • First, the patient with suspected malaria should have it confirmed either using microscopy or a rapid diagnostic test (RDT);
    • Next, simple infections should be treated with fast-acting artemisinin-based combination therapy (ACT);
    • In areas with low malaria rates, a single dose of primaquine should be added to this treatment to reduce the chance of malaria spreading further;
    • Severe cases of malaria should be treated with injectable artesunate for at least 24 hours. Once the patient can take oral medicines, they should complete a three-day course of artemisinin-based combination therapy.

    WHO Response

    The current response of WHO to the threat posed by malaria is contained in the Global Technical Strategy for Malaria 2016-2030 adopted by the World Health Assembly in May 2015.  The strategy provides comprehensive technical guidance to countries and development partners. It set the ambitious target of reducing the global malaria burden by 90% by 2030 through implementation of its three pillars with two supporting elements.

    • Pillar One: Ensure universal access to malaria prevention, diagnosis and treatment
    • Pillar Two: Accelerate efforts towards elimination and attainment of malaria-free status
    • Pillar Three: Transform malaria surveillance into a core intervention
    • Supporting Element 1: Harnessing innovation and expanding research
    • Supporting Element 2: Strengthening the enabling environment.

    In August 2016, the WHO Regional Committee for Africa adopted the “Framework for implementing the Global Technical Strategy for malaria 2016–2030 in the African Region”. This framework guides implementation of the GTS in the WHO African Region.

    At the World Health Assembly in May 2018, Dr Tedros Adhanom Ghebreyesus, WHO Director-General, announced a redoubling of efforts to combat malaria.  Six months later, a new strategy known as “high burden to high impact” was launched. This approach will be driven by the eleven countries most affected by malaria.  Ten of these countries – Burkina Faso, Cameroon, the Democratic Republic of the Congo, Ghana, Mali, Mozambique, Niger, Nigeria, Uganda and United Republic of Tanzania – are in sub-Saharan Africa.  In 2017, these countries reported increases in malaria cases over the previous year.  The “high burden to high impact” strategy advocates a country-led approach, and rests on the following four key elements: ensuring political will exists to reduce malaria deaths; improving information and data analysis to maximize impact; better guidance, policies and strategies; and ensuring a coordinated malaria response at the national level.

    Key fact

    Asset 4

    15.7 million children

    in 12 countries in Africa’s Sahel region were protected through seasonal malaria chemoprevention programmes in 2017.

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    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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