Chloroquine-resistant Plasmodium vivax malaria in Peru

Trenton K. Ruebush, Jorge Zegarra, Javier Cairo, Ellen M. Andersen, Michael Green, Dylan R. Pillai, Wilmer Marquiño, María Huilca, Ernesto Arévalo, Coralith Garcia, Lely Solary, Kevin C. Kain

Research output: Contribution to journalArticlepeer-review

91 Scopus citations


Reports from several sites in South America suggest the presence of isolated cases of chloroquine-resistant Plasmodium vivax malaria. To investigate the possibility of chloroquine-resistant P. vivax in Peru, we conducted 28-day in vivo drug efficacy trials at three sites in the Amazon region and one site on the northern Pacific Coast between 1998 and 2001. A total of 242 patients between the ages of 2 and 60 years were enrolled (177 from the Amazon region and 65 from the northern coast). All subjects received directly observed therapy with chloroquine, 25 mg/kg, over a three-day period. On enrollment, 49% had a documented fever and 96% had a history of fever; their geometric mean parasite density was 5,129 parasites/μL. A total of 212 (88%) of the 242 subjects completed their 28-day follow-up. Four of the 177 patients from the Amazon region had a recurrence of P. vivax parasitemia on days 21 and 28 after treatment was initiated. Two of these patients had chloroquine-resistant infections, based on polymerase chain reaction-single-stranded conformational polymorphism genotyping and chloroquine-desethylchloroquine blood levels, which were ≥ 97 ng/mL at the time of the reappearance of parasitemia. None of the subjects studied on the northern Pacific Coast had recurrent parasitemia.

Original languageEnglish (US)
Pages (from-to)548-552
Number of pages5
JournalAmerican Journal of Tropical Medicine and Hygiene
Issue number5
StatePublished - Nov 2003
Externally publishedYes

ASJC Scopus subject areas

  • Parasitology
  • Virology
  • Infectious Diseases


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