5.3.2  Incubation period of malaria

When a person becomes infected with one of the Plasmodium parasites that cause malaria, he or she will not feel sick immediately. The period between infection with the parasites that cause the disease and the beginning of malaria symptoms is called the malaria incubation period. The infected person may feel normal from 7 to 21 days when infected with Plasmodium parasites. P. falciparum has a shorter incubation period (7 to 14 days) than P. vivax (12 to 18 days). Plasmodium malariae tends to have a much longer incubation period, as you can see from Table 5.1.

As you will learn in Study Session 7, Plasmodium infection causes fever in cycles or episodes which occur at either 48 or 72 hour intervals. Episodes of fever occur when the parasites are released into the blood and infect new red blood cells (see Figure 5.5).