Malaria Parasite Species

Characteristics of Malaria Parasites

• Malaria in humans is caused by six species of Plasmodium parasites: P. falciparum, P. vivax, P. ovale wallikeri, P. ovale curtisi, P. malariae, and P. knowlesi, according to the Clinical Microbiology and Infection guidelines 1, 2
• Plasmodium falciparum is the most virulent species and responsible for the majority of malaria-related deaths, particularly in sub-Saharan Africa, with a high mortality burden 1
• Plasmodium falciparum can rapidly progress to severe malaria with life-threatening complications including cerebral malaria, severe anemia, metabolic acidosis, and multi-organ failure, as reported by the Clinical Microbiology and Infection guidelines 1, 3
• Plasmodium vivax forms dormant liver-stage hypnozoites that cause relapsing infections weeks to months after initial infection, and accounted for 74.6% of locally acquired mosquito-transmitted malaria outbreaks in the United States from 1957-2003, according to the MMWR Recommendations and Reports 4
• Plasmodium ovale has two distinct subspecies: P. ovale wallikeri and P. ovale curtisi, which also form dormant liver hypnozoites causing relapsing infections similar to P. vivax, as reported by the Clinical Microbiology and Infection guidelines 1, 2
• Plasmodium knowlesi is a simian parasite that causes a significant portion of human malaria cases in parts of Southeast Asia, and can cause severe disease with rapid parasite multiplication, according to the Clinical Infectious Diseases guidelines 5, 6
• Other simian Plasmodium species restricted to South America and Southeast Asia can occasionally infect humans, as reported by the Clinical Microbiology and Infection guidelines 1, 2