Classification of malaria by the clinical pattern of fever

• P. vivax and P. ovale: cause benign tertian malaria
• P. falciparum causes malignant tertian malaria
• P. malariae causes benign quartan malaria

Each of the four types of malarial parasite cause a characterisitic periodicity of fever. This has led to the description of malaria as being either tertian, where fever occurs every third day i.e. day 1,3,5 etc. or quartan where fever occurs every fourth day ie on day 1,4,7 etc. Many cases of infection by P. falciparum may also be described as subtertian and quotidian i.e. daily.

In some cases of malaria however, the characteristic pattern of fever may not be present in the early stages of infection.