1) Protozoan disease caused in humans by four species of the genus Plasmodium (P. falciparum, P. vivax, P. ovale, and P. malariae) and transmitted by the bite of an infected female mosquito of the genus Anopheles; malaria is endemic in parts of Asia, Africa, Central and South America, Oceania, and certain Caribbean islands; characterized by extreme exhaustion associated with paroxysms of high fever, sweating, shaking chills, and anemia; malaria in animals is caused by other species of plasmodia.

2) An acute or chronic disease caused by the presence of sporozoan parasites of the genus Plasmodium in the red blood cells, transmitted from an infected to an uninfected individual by the bite of anopheline mosquitoes, and characterized by periodic attacks of chills and fever that coincide with mass destruction of blood cells and the release of toxic substances by the parasite at the end of each reproductive cycle .

2) Any of various diseases of birds and mammals that are more or less similar to malaria of human beings and are caused by blood protozoans.