title: Increased frequency of chloroquine resistant P. falciparum on a rubber estate in Peninsular Malaysia during two years of systematic chloroquine treatment.
abstract: Chloroquine pressure was applied over a 22 month period on a somewhat isolated, malarious rubber estate by examination of residents at 4-week intervals and treatment of parasitaemias with chloroquine. During this time the monthly attack rate for P. falciparum rose four-fold to an average of nearly 18% per month, while that of P. vivax remained relatively constant at about 8%. Eight in vivo chloroquine resistance studies, which allowed both detection of late recrudescing R-I resistance and estimation of the risk of reinfection, showed an apparent rise in the drug resistance rate, from 12% to 20% prior to the study to the range of 40-50%. Virtually all resistance encountered was R-I in nature. There was no convincing evidence of chloroquine resistance among 148 tested P. vivax infections.
mesh_terms: D001769:Blood / Q000469:parasitology; D002738:Chloroquine / Q000494:pharmacology / Q000627:therapeutic use*; D004352:Drug Resistance, Microbial; D006801:Humans; D008137:Longitudinal Studies; D008288:Malaria / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control; D008296:Malaysia; D010963:Plasmodium falciparum / Q000187:drug effects; D011815:R Factors; D012008:Recurrence
chemical_list: D002738:Chloroquine