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Date of this Version



Clinical Infectious Diseases 2011;52(5):621–623


The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. 2011. All rights reserved.


Douglas et al [1] describe patency with Plasmodium vivax in the 63 days after treatment of malaria caused by Plasmodium falciparum in >10,000 subjects in Thailand over a 14-year period who received 25 different therapies. Therapy for acute malaria aims at the asexual stages of the organism infecting blood. Among the many blood schizontocidal drugs that achieve this therapeutic effect, none eliminate dormant stages in the liver, which are known as hypnozoites. Regardless of the species being treated, if hypnozoites are present, relapse may occur in the absence of treatment with primaquine, which is the only registered hypnozoitocide. The patients evaluated by Douglas et al [1] did not receive hypnozoitocidal therapy for the simple reason that it is not indicated for falciparum malaria. Parasitemia with P. vivax occurred in 20%–51% of these patients, with that rate correlated to the rapidity of excretion of drugs administered against P. falciparum.