Malaria is a life-threatening disease caused by the Plasmodium parasites, which are spread to people through the bites of infected Anopheles mosquitoes. Malaria causes an estimated 249 million cases and 608,000 deaths per year in 85 countries. The African region accounts for 94 percent of cases and 95 percent of deaths with children under 5 years of age accounting for approximately 80 percent of all malaria deaths in the region (a child in Africa dies every minute from malaria). Asia, Latin America, and to a lesser extent the Middle East and parts of Europe are also affected.
Pregnant women, infants, children less than 5 years of age, people living with HIV and travellers are at a higher risk of severe infection.
There are five parasite species that cause malaria in humans: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale and Plasmodium knowlesi. P. falciparum and P. vivax are the most common and Plasmodium falciparum is the deadliest. For both P. vivax and P. ovale, clinical relapses may occur weeks to months after the first infection, even if the patient has left the malaria prone area. These new episodes arise from dormant liver forms known as hypnozoites, Special treatment – targeted at these liver stages – is required for a complete cure.
Early diagnosis (using parasite-based diagnostic testing through microscopy or a rapid diagnostic test) and treatment of malaria reduces disease and prevents deaths. It also contributes to reducing malaria transmission. The best available treatment, particularly for P. falciparum malaria, is artemisinin-based combination therapy (ACT).
In recent years, parasite resistance to artemisinin’s has been detected in 5 countries: Myanmar, Laos, Cambodia, Thailand and Viet Nam. The use of oral artemisinins monotherapy is thought to be an important cause. If resistance to artemisinins develops and spreads to other geographical areas, the public health consequences could be serious.
Vector control is the main way to reduce malaria transmission at the community level using long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) with insecticides. A number of public health distribution programmes provide free LLINs. Countries in sub-Saharan Africa and India are of significant concern. These countries are characterized by high levels of malaria transmission and widespread reports of insecticide resistance. Longer-lasting forms of existing IRS insecticides (pyrethroids), as well as new classes of insecticides for use in IRS programmes, are under development. Antimalarial medicines can also be used to prevent malaria.
Two vaccines have been recommended to date- the RTS,S/AS01 and the R21/Matrix-M malaria vaccine among children living in regions with moderate to high P. falciparum malaria transmission.