Malaaria

Malaaria, commonly known as malaria in many languages, is a parasitic disease caused by Plasmodium species and transmitted to humans by Anopheles mosquitoes. The most important human-infecting species are P. falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi.

Transmission occurs when an infected female Anopheles mosquito feeds on a person, injecting sporozoites that invade liver cells and later red blood cells. The incubation period ranges from about 7 to 40 days, depending on the species and geographical region.

Clinical features include fever, chills, sweats, headaches, nausea and malaise. In falciparum malaria, symptoms can progress rapidly to severe disease such as anemia, cerebral malaria, acute respiratory distress and organ failure, particularly in children and non-immune adults. Some infections cause relapses or recrudescence, especially P. vivax and P. ovale, due to dormant liver stages.

Diagnosis relies on microscopy of stained blood smears or rapid diagnostic tests that detect parasite antigens. Molecular methods exist but are mainly used in reference laboratories.

Treatment depends on species and resistance patterns. Artemisinin-based combination therapies are first-line for P. falciparum in most regions. Chloroquine remains effective only in areas with sensitive strains. Primaquine is used to eradicate liver-stage parasites in vivax and ovale infections. Severe malaria requires urgent intravenous therapy (often artesunate) and supportive care.

Prevention focuses on vector control (insecticide-treated nets, indoor residual spraying), chemoprophylaxis for travelers, and preventive treatment in pregnancy. A malaria vaccine, RTS,S/AS01, has been piloted in several regions and recommended by WHO for young children in endemic areas where the disease remains common.

Malaaria remains a global health issue, with most cases concentrated in sub-Saharan Africa, parts of South and Southeast Asia, and parts of Latin America. Efforts to reduce transmission and improve treatment access have substantially lowered mortality, but challenges include insecticide and drug resistance and funding gaps.