title: Chloroquine-resistant Plasmodium vivax malaria in Peru.
abstract: 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/microL. 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 > or = 97 ng/mL at the time of the reappearance of parasitemia. None of the subjects studied on the northern Pacific Coast had recurrent parasitemia.
authors.affiliation: Office of the Director, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA. tkr1@cdc.gov
authors.forename: Trenton K
authors.initials: TK
authors.lastname: Ruebush
authors.forename: Jorge
authors.initials: J
authors.lastname: Zegarra
authors.forename: Javier
authors.initials: J
authors.lastname: Cairo
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Andersen
authors.forename: Michael
authors.initials: M
authors.lastname: Green
authors.forename: Dylan R
authors.initials: DR
authors.lastname: Pillai
authors.forename: Wilmer
authors.initials: W
authors.lastname: Marquiño
authors.forename: María
authors.initials: M
authors.lastname: Huilca
authors.forename: Ernesto
authors.initials: E
authors.lastname: Arévalo
authors.forename: Coralith
authors.initials: C
authors.lastname: Garcia
authors.forename: Lely
authors.initials: L
authors.lastname: Solary
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Kain
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine / Q000494:pharmacology*; D016054:DNA, Protozoan / Q000032:analysis; D004351:Drug Resistance; D005260:Female; D006801:Humans; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000469:parasitology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010568:Peru / Q000453:epidemiology; D010966:Plasmodium vivax / Q000187:drug effects* / Q000235:genetics; D016133:Polymerase Chain Reaction; D012008:Recurrence
chemical_list: D000962:Antimalarials; D016054:DNA, Protozoan; D002738:Chloroquine