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MICROBIOLOGY AND EPIDEMIOLOGY
Six major species of Plasmodium cause nearly all cases of human disease: P. falciparum, P. vivax, two morphologically identical sympatric species of P. ovale, P. malariae, and P. knowlesi.
- P. falciparum, the cause of most cases of severe disease and most deaths, predominates in Africa, New Guinea, and Hispaniola.
- P. vivax is more common in Central America.
- P. falciparum and P. vivax are equally prevalent in South America, the Indian subcontinent, eastern Asia, and Oceania.
- P. ovale makes up <1% of isolates outside Africa.
- P. malariae is found in most areas (especially throughout sub-Saharan Africa) but is less common.
- P. knowlesi (the monkey malaria parasite) can reliably be identified only by molecular techniques and is present in Borneo and Southeast Asia.
- Malaria is the most important parasitic disease in humans, causing ∼1200 deaths each day.