Species of Plasmodium parasites

Species of Plasmodium parasites

  1. P. vivax is the second most significant parasite causing malaria (approximately 2% of all cases) and is prevalent in Southeast Asia and Latin America. P. vivax and P. ovale trigger a blood stage infection causing an acute malaria episode but have the added complication of a liver stage infection, where the parasites (hypnozoites) can lie dormant and reactivate if left untreated. This can cause relapses that may occur weeks or months after the initial infection. This makes P. vivax a particular challenge for elimination efforts, with transmission driven largely by relapse from dormant liver stages.1

For many years, P. vivax malaria was considered relatively benign. However, evidence has emerged that it can also lead to severe disease and death,2 with young children and pregnant women at highest clinical risk.3

Achieving what is referred to as ‘radical cure’ for P. vivax, that is clearing all the parasites present in the patient, involves treating both the blood and liver stages of infection.

Visit the P. vivax malaria hub to learn more about its symptoms and treatment options

  1. Together with P. malariae, P. vivax represents only a small percentage of global infections. P. malariae causes milder symptoms than either of the two parasites above.
  2. A fifth species, P. knowlesi, primarily infects primates, but has also led to human malaria, though the exact mode of transmission remains unclear.

Learn more about relapsing malaria

1. Chu CS, White NJ. “Management of relapsing Plasmodium vivax malaria” Expert Rev Anti Infect Ther. 14(10):885-900 (2016), doi: 10.1080/14787210.2016. 1220304
2. Price RN et al. “Vivax malaria: neglected and not benign” Am J Trop Med Hyg. 77(6 Suppl):79–87 (2007), PMCID: PMC2653940
3. Phyo AP et al. “Clinical impact of vivax malaria: A collection review” PLoS Med. 19(1): e1003890 (2022), doi: 10.1371/journal. pmed.1003890 Fernando D et al. “Cognitive performance at school entry of children living in malariaendemic areas of Sri Lanka” Trans R Soc Trop Med Hyg. 97(2):161-5 (2003), doi: 10.1016/s0035- 9203(03)90107-6