Malaria

Malaria is an acute febrile infectious disease caused by protozoan parasites of the genus Plasmodium, transmitted to humans through the bite of infected female Anopheles mosquitoes. Five species are known to cause human malaria: Plasmodium falciparum (the most severe form), P. vivax, P. ovale, P. malariae, and P. knowlesi. The disease primarily affects the blood and the liver, as parasites initially multiply in hepatocytes before invading red blood cells, leading to their cyclical destruction (hemolysis). This results in the hallmark symptoms of recurring episodes of high fever, rigors (chills and shaking), profuse sweating, headache, malaise, and anemia. Other commonly affected organ systems include the spleen (splenomegaly), the brain (cerebral malaria, particularly with P. falciparum), the kidneys, and the lungs. P. falciparum malaria can rapidly progress to severe and life-threatening complications including cerebral malaria (altered consciousness, seizures, coma), severe anemia, acute respiratory distress syndrome (ARDS), metabolic acidosis, hypoglycemia, renal failure, and multi-organ dysfunction. P. vivax and P. ovale infections can cause relapses months or years after the initial infection due to dormant liver-stage parasites called hypnozoites. P. malariae can persist as a chronic low-grade blood-stage infection for decades if untreated. Malaria remains one of the most significant global infectious diseases, predominantly affecting tropical and subtropical regions of sub-Saharan Africa, South and Southeast Asia, and parts of Central and South America. Treatment depends on the species and severity: uncomplicated P. falciparum malaria is treated with artemisinin-based combination therapies (ACTs), while chloroquine remains effective for P. vivax, P. ovale, and P. malariae in most regions. Severe malaria requires intravenous artesunate as first-line therapy. Primaquine or tafenoquine is used to eliminate hypnozoites in P. vivax and P. ovale infections. Preventive measures include insecticide-treated bed nets, indoor residual spraying, chemoprophylaxis for travelers, and the recently approved RTS,S/AS01 (Mosquirix) vaccine for children in endemic areas. Host genetic factors such as sickle cell trait, thalassemias, glucose-6-phosphate dehydrogenase deficiency, and Duffy-negative blood group confer varying degrees of protection against malaria.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Malaria