Walsh & Hoyt: Epidemiology

Malaria is a major cause of morbidity and mortality worldwide, with an estimated 300500 million cases occurring annually, causing about 2 million deaths per year. In some countries, malaria is a major health concern. In Papua New Guinea, for example, malaria is the third most common cause of death and the second most common cause of illness. P. vivax is the predominant cause of malaria in India, Pakistan, and Central America; malaria caused by P. falciparum occurs much less frequently in these countries but is common in Africa, Haiti, and New Guinea. Both P. falciparum and P. vivax are common causes of malaria in Southeast Asia and South America. P. ovale causes malaria primarily in Africa and rarely in other parts of the world, whereas P. malariae causes small numbers of cases throughout the world. The prevalence of different species of Plasmodium has shifted over time as a result of public health measures, which have varying effectiveness for the different species. Malaria is not endemic in either the United States or Europe but occurs as imported or induced cases. Imported cases are related to military personnel involvement in endemic regions (e.g., Vietnam), to travel to endemic areas by Americans, and to travel to the United States by citizens from endemic countries. As noted before, cases of malaria may occur from laboratory accidents.