Malaria

28 June 2019

Every 2 minutes, a child dies of malaria. And each year, more than 200 million new cases of the disease are reported. Although countries have dramatically reduced the total number of malaria cases and deaths since 2000, progress in recent years has stalled. Worryingly, in some countries, malaria is on the rise.

WHO/S. Torfinn

Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. It is preventable and curable.

Malaria is caused by Plasmodium parasites that are spread to people through the bites of infected Anopheles mosquito vectors. Of the 5 parasite species that cause malaria in humans, P. falciparum is the most deadly. The first symptoms of malaria – fever, headache, and chills – usually appear 10–15 days after the infective mosquito bite. Left untreated, P. falciparum malaria can progress to severe illness and death.

WHO/Chris Black

Sub-Saharan Africa carries the heaviest malaria burden

In 2017, there were an estimated 219 million cases of malaria in 87 countries. While approximately 90% of malaria cases and deaths occur in sub-Saharan Africa, many people living in the WHO regions of South-East Asia, Eastern Mediterranean, Western Pacific, and the Americas are also at risk of contracting the disease.

WHO

Children under 5 are particularly vulnerable

Children under the age of 5 are the most vulnerable group affected by malaria. In 2017, an estimated 266 000 children died of malaria before their fifth birthday, accounting for 61% of all malaria deaths worldwide.

WHO/G. Osodi

Pregnant women are also at high risk of malaria

Pregnant women are also at considerably higher risk of contracting malaria, and developing severe disease, than other populations. Malaria in pregnancy increases the risk of maternal and fetal anaemia, stillbirth, spontaneous abortion, low birth weight and infant death.

WHO/A. Loke
Lowering the burden of malaria in high-risk areas entails more than just distributing mosquito nets. ASHAs go door to door at night – when the mosquitoes bite – to ensure the nets are being used correctly.

Sleeping under insecticide-treated mosquito nets protects against malaria

WHO recommends the use of insecticide-treated nets (ITNs) for all populations at risk of malaria, even in settings where transmission of the disease has been markedly reduced. In 2017, an estimated 50% of people at risk of malaria in sub-Saharan Africa slept under an ITN, an increase from 29% in 2010. However, ITN coverage has only marginally improved since 2015.

WHO/A. Loke
Indoor residual spraying (IRS) – which involves spraying insecticides on the indoor walls and ceilings of homes – is another powerful way to rapidly reduce malaria transmission. Here, an IRS worker sprays a home in the Kandhamal district of Odisha.

Indoor residual spraying is another powerful way to rapidly reduce malaria transmission

Indoor residual spraying (IRS) involves spraying the inside walls of housing structures with insecticides, typically once or twice per year. Globally, the protection offered by IRS has declined from a peak of 5% in 2010 to 3% in 2017, with decreases seen across all WHO regions.

WHO/T. Trenchard

Early diagnosis and prompt treatment of malaria prevents deaths

Early diagnosis and treatment of malaria reduces disease and prevents deaths. It also contributes to reducing malaria transmission. Access to diagnostic testing and treatment should be seen not only as a component of malaria control but as a fundamental right of all populations at risk.

WHO/R. Memba Paquete
There were 219 million malaria cases in 2017. 70% were in 11 countries.

The global malaria burden remains heavily concentrated in a small group of countries

In 2017, 11 countries – 10 in sub-Saharan Africa plus India – accounted for about 70% of malaria cases and deaths globally. Among the 10 highest burden African countries, there were an estimated 3.5 million more cases in 2017 over the previous year. Malaria can trap families and communities in a downward spiral of poverty, disproportionately affecting marginalized and poor people who cannot afford treatment or who have limited access to health care.

© WHO/Christine McNab
China is a good example of what happens when a country is determined to eliminate malaria – this became the joint goal of 13 ministries, including health, finance, industry, and education.

In some countries, the pace towards zero malaria cases is quickening

Although global progress against malaria has levelled off, a sub-set of countries with a low burden of malaria are moving quickly towards elimination. According to WHO’s latest World malaria report, the number of countries with less than 100 indigenous cases of malaria – a strong indicator that elimination is within reach – increased from 15 in 2010 to 26 in 2017. Since 2018, 4 countries have been certified by WHO as malaria-free: Algeria, Argentina, Paraguay and Uzbekistan.

WHO/V. Sokhin

The immediate threat of antimalarial drug resistance is low

Despite the presence of multidrug resistance in the Greater Mekong, countries across the subregion continue to report a downward trend in malaria cases and deaths. To date, there have been effective treatment options for all malaria parasites detected globally and, overall, the immediate threat of antimalarial drug resistance is low.

WHO/T. Trenchard
Two researchers are seen observing the behaviour of female Anopheles mosquitoes that are being bred at the laboratory of Manhiça Health Research Centre.

Insecticide resistance is more widespread

Of the 80 malaria-affected countries that provided data for the period 2010–2017, resistance to at least 1 of 4 insecticide classes in one malaria vector was detected in 68 countries. Resistance to pyrethroids – the only insecticide class currently used in insecticide-treated nets (ITNs) – is now widespread. However, ITNs continue to be an effective tool for malaria prevention, even in areas where mosquitoes have developed resistance to pyrethroids, as evidenced by a large multi-country evaluation coordinated by WHO.

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