In humans, the set of diseases caused by infection by the protozoans Plasmodium vivax causing the tertian type, P. Malariae the quartan type and P. Falciparum the quotidian or irregular type of disease, the names referring to the frequency of fevers. The fevers occur when the merozoites are released from the erythrocytes. The organisms are transmitted by the Anopheles mosquito.

(11 Mar 2008)