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Why can Plasmodium vivax malaria return months or years after an earlier illness?
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malaria
Life cycle of a malaria parasite.
Plasmodium vivax malaria can return months or years after an initial infection because some of the parasites do not immediately enter the bloodstream to infect red blood cells. Instead, they remain in the liver in a dormant state known as a "hypnozoite."
These dormant forms can persist for extended periods before eventually emerging to attack red blood cells, which results in a relapse of the disease.1