Relapses of Plasmodium vivax infection usually result from activation of heterologous hypnozoites

Mallika Imwong, Georges Snounou, Sasithon Pukrittayakamee, Naowarat Tanomsing, Ryong Kim Jung, Amitab Nandy, Jean Paul Guthmann, Francois Nosten, Jane Carlton, Sornchai Looareesuwan, Shalini Nair, Daniel Sudimack, Nicholas P J Day, Timothy J C Anderson, Nicholas J. White

Research output: Contribution to journalArticlepeer-review


Background. Relapses originating from hypnozoites are characteristic of Plasmodium vivax infections. Thus, reappearance of parasitemia after treatment can result from relapse, recrudescence, or reinfection. It has been assumed that parasites causing relapse would be a subset of the parasites that caused the primary infection. Methods. Paired samples were collected before initiation of antimalarial treatment and at recurrence of parasitemia from 149 patients with vivax malaria in Thailand (n = 36), where reinfection could be excluded, and during field studies in Myanmar (n = 75) and India (n = 38). Results. Combined genetic data from 2 genotyping approaches showed that novel P. vivax populations were present in the majority of patients with recurrent infection (107 [72%] of 149 patients overall [78% of patients in Thailand, 75% of patients in Myanmar {Burma}, and 63% of patients in India]). In 61% of the Thai and Burmese patients and in 55% of the Indian patients, the recurrent infections contained none of the parasite genotypes that caused the acute infection. Conclusions. The P. vivax populations emerging from hypnozoites commonly differ from the populations that caused the acute episode. Activation of heterologous hypnozoite populations is the most common cause of first relapse in patients with vivax malaria.

Original languageEnglish (US)
Pages (from-to)927-933
Number of pages7
JournalJournal of Infectious Diseases
Issue number7
StatePublished - Apr 1 2007

ASJC Scopus subject areas

  • General Medicine


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