|Source: James Gathany/CDC|
Malaria is a blood-borne infection caused by parasites and transmitted to people by the bite of female Anopheles mosquitoes, which are active from dusk to dawn. Malaria usually begins as a flu-like illness with fever and chills. Mild to moderate anemia is also common because the malaria parasite infects and destroys red blood cells. Untreated, malaria can result in severe anemia, lung and kidney failure, coma, and death.
Malaria typically occurs in tropical and subtropical regions of the world, particularly in sub-Saharan Africa, where the mosquito and the malaria parasite thrive. Four species of malaria parasites infect humans, although two species, Plasmodium falciparum and P. vivax, account for about 90 percent of all human infections. In sub-Saharan Africa, the majority of infections are caused by P. falciparum, which causes the most severe form of the disease and almost all deaths worldwide.
In most malarious areas transmission varies by season, with the highest rates occurring during the rainy season. In areas with high levels of transmission, residents build up immunity over time and are relatively protected against malaria. People can lose their immunity if they move away from the area and are no longer constantly exposed to infections. In areas of low transmission, malaria epidemics can be large and devastating. While all people living in malarious areas can be infected, children under 5 years of age, pregnant women, and people living with HIV/AIDS are most vulnerable to malaria.
Malaria is a disease that can be prevented and treated with cost-effective and proven interventions. The most effective antimalarial drugs currently available are artemisinin-based combination therapies (ACTs), which have become standard in most malaria-affected regions. Diagnosis of most malaria cases is based solely on clinical grounds, without laboratory confirmation. Diagnosis is challenging because the symptoms and signs of malaria are not specific to malaria so many people treated for malaria do not have the infection. Because of the high cost of ACTs, the need for accurate diagnosis of malaria – through either examination of a blood sample under a microscope or with a rapid diagnostic test – is essential to the success of national malaria control programs. Cost-effective and proven prevention measures include the use of insecticide-treated mosquito nets, indoor residual spraying with insecticides, and intermittent preventive treatment of malaria during pregnancy.
Learn more about malaria.