Infectious agent: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and less common Plasmodium knowlesi.
Description of illness: Malaria is a serious and sometimes fatal disease caused by Plasmodium parasites. Four types of malaria parasites commonly infect humans: P. falciparum, P. vivax, P. ovale and P. malariae. Of these, P. falciparum is most likely to result in severe illness, while P. vivax and P. ovale can cause relapsing malaria. The parasites are transmitted by Anopheles mosquitos. Malaria is not transmitted person to person through contact, although it can be transmitted through blood or organs from an infected donor or from a pregnant woman to her infant. Symptoms usually begin 1 to 4 weeks after infection and typically include high fevers, shaking chills and flu-like illness. Anemia and jaundice may also occur. If not promptly treated, the infection can cause kidney failure, seizures, confusion, coma and death.