World Malaria Day is marked each year on 25 April and brings together the global malaria community to highlight global efforts to end malaria. It is an opportunity for us to keep malaria high on the global health agenda, with this year’s theme: Time to Deliver Zero Malaria: Invest, Innovate, Implement.

This years theme highlights the need for urgent action and further investment to ensure investments made to date deliver maximum impact in the fight to end malaria.

What is malaria and how is it transmitted?

Malaria is a life-threatening disease primarily found in tropical countries. It is both preventable and curable. However, without prompt diagnosis and effective treatment, a case of uncomplicated malaria can progress to a severe form of the disease, which is often fatal without treatment.

Malaria is not contagious and cannot spread from one person to another; the disease is transmitted through the bites of female Anopheles mosquitoes.  Five species of parasites can cause malaria in humans and 2 of these species – Plasmodium falciparum and Plasmodium vivax – pose the greatest threat. There are over 400 different species of Anopheles mosquitoes and around 40, known as vector species, can transmit the disease.

This risk of infection is higher in some areas than others depending on multiple factors, including the type of local mosquitoes. It may also vary according to the season, the risk being highest during the rainy season in tropical countries. 

What are the symptoms and how is it diagnosed?

The first symptoms of malaria usually begin within 10–15 days after the bite from an infected mosquito. Fever, headache and chills are typically experienced, though these symptoms may be mild and difficult to recognize as malaria. In malaria endemic areas, people who have developed partial immunity may become infected but experience no symptoms (asymptomatic infections).

WHO recommends prompt diagnosis for anyone with suspected malaria. If Plasmodium falciparum malaria is not treated within 24 hours, the infection can progress to severe illness and death. Severe malaria can cause multi-organ failure in adults, while children frequently suffer from severe anaemia, respiratory distress or  cerebral malaria. Human malaria caused by other Plasmodium species can cause significant illness and occasionally life-threatening disease.

Malaria can be diagnosed using tests that determine the presence of the parasites causing the disease. There are 2 main types of tests: microscopic examination of blood smears and rapid diagnostic tests. Diagnostic testing enables health providers to distinguish malarial from other causes of febrile illnesses, facilitating appropriate treatment.  

What treatments are available for malaria?

Malaria is a treatable disease. Artemisinin-based combination therapies (ACTs) are the most effective antimalarial medicines available today and the mainstay of recommended treatment for Plasmodium falciparum malaria, the deadliest malaria parasite globally.

ACTs combine 2 active pharmaceuticals with different mechanisms of action, including derivates of artemisinin extracted from the plant Artemisia annua and a partner drug. The role of the artemisinin compound is to reduce the number of parasites during the first 3 days of treatment, while the role of the partner drug is to eliminate the remaining parasites.

As no alternative to artemisinin derivatives is expected to enter the market for several years, the efficacy of ACTs must be preserved, which is why WHO recommends that treatment should only be administered if a person tests positive for malaria. WHO does not support the promotion or use of Artemisia plant material (whether teas, tablets or capsules) for the prevention or treatment of malaria.

Over the last decade, parasite resistance to antimalarial medicines has emerged as a threat in the fight against malaria, particularly in the Greater Mekong subregion. WHO is also concerned about more recent reports of drug-resistant malaria in Africa. To date, resistance has been documented in 3 of the 5 malaria species known to affect humans: P. falciparumP. vivax, and P. malariae. However, nearly all patients infected with artemisinin-resistant parasites who are treated with an ACT are fully cured, provided the partner drug is highly efficacious.

How can malaria be prevented?

Malaria is a preventable disease. 

1. Vector control interventions. Vector control is the main approach to prevent malaria and reduce transmission. Two forms of vector control are effective for people living in malaria-endemic countries: insecticide-treated nets, which prevent bites while people sleep and which kill mosquitoes as they try to feed, and indoor residual spraying, which is the application of an insecticide to surfaces where mosquitoes tend to rest, such as internal walls, eaves and ceilings of houses and other domestic structures. For travellers, the use of an insecticide-treated net is the most practical vector control intervention. WHO maintains a list vector control products that have been assessed for their safety, effectiveness and quality.  

2. Chemopreventive therapies and chemoprophylaxis. Although designed to treat patients already infected with malaria, some antimalarial medicines can also be used to prevent the disease. Current WHO-recommended malaria chemopreventive therapies for people living in endemic areas include intermittent preventive treatment of malaria in pregnancy, perennial malaria chemoprevention, seasonal malaria chemoprevention, post-discharge malaria chemoprevention, and intermittent preventive treatment of malaria for school-aged children. Chemoprophylaxis drugs are also given to travellers before entering an area where malaria is endemic and can be highly effective when combined with insecticide-treated nets. 


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