A molecular surveillance system for global patterns of drug resistance in imported malaria

Emerg Infect Dis. 2003 Jan;9(1):33-6. doi: 10.3201/eid0901.020121.

Abstract

Analysis of imported malaria in travelers may represent a novel surveillance system for drug-resistant malaria. We analyzed consecutive falciparum malaria isolates from Canadian travelers from 1994 to 2000, for polymorphisms in pfcrt, dhfr, and dhps linked to chloroquine and pyrimethamine/sulfadoxine resistance. Forty percent of isolates possessed the K76 pfcrt allele, suggesting that many imported falciparum infections are still responsive to chloroquine. Travelers who had recently taken chloroquine had a significantly increased risk of harboring isolates with pfcrt resistance alleles (odds ratio = 4.47; p=0.03). The presence of two or more mutations in dhfr or dhps was found in 64.8% (95% confidence interval [CI] 54.6 to 73.9) and in 30.4% (95% CI 21.7 to 40.3) of isolates, respectively, and increased significantly over the course of the study. These molecular markers indicate that pyrimethamine/sulfadoxine resistance is increasing and is now too high to rely on this drug as a routine therapeutic agent to treat malaria in travelers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Animals
  • Antimalarials / pharmacology
  • Child
  • Child, Preschool
  • Chloroquine / pharmacology
  • Drug Resistance / genetics*
  • Female
  • Genetic Markers*
  • Humans
  • Infant
  • Malaria, Falciparum / epidemiology*
  • Malaria, Falciparum / parasitology
  • Male
  • Middle Aged
  • Mutation
  • Plasmodium falciparum / drug effects*
  • Plasmodium falciparum / genetics
  • Population Surveillance*
  • Protozoan Proteins / genetics
  • Pyrimethamine / pharmacology
  • Sulfadoxine / pharmacology
  • Travel*

Substances

  • Antimalarials
  • Genetic Markers
  • Protozoan Proteins
  • Sulfadoxine
  • Chloroquine
  • Pyrimethamine