Malaria in which sporulation occurs each 48 hr. Symptoms are more common during the day. Paroxysms are divided into chill, fever, and sweating stages. Cold stage is usually 10 to 15 min but may last an hour or more. Febrile stage varies from 4 to 6 hr. Benign tertian malaria is caused by Plasmodium vivax, malignant tertian malaria by Plasmodium falciparum.