Molecular Surveillance of Plasmodium falciparum Drug Resistance Markers in Clinical Samples from Botswana

Am J Trop Med Hyg. 2018 Dec;99(6):1499-1503. doi: 10.4269/ajtmh.18-0440.

Abstract

Drug-resistant Plasmodium falciparum is a major threat to global malaria control and elimination efforts. In Botswana, a southern African country approaching malaria elimination, P. falciparum molecular data are not available. Parasites were assessed through pollymerase chain reaction (PCR) for confirmation of positive rapid diagnostic tests, multiplicity of infection (MOI), and drug resistance markers among isolates from clinical uncomplicated malaria cases collected at health facilities. Of 211 dried blood spot samples selected for the study, 186 (88.2%) were PCR positive for P. falciparum. The mean MOI based on MSP1 genotyping was 2.3 and was not associated with age. A high prevalence of wild-type parasites for pfcrt and pfmdr1 was found, with a haplotype frequency (K76/N86) of 88.8% and 17.7% of the isolates having two copies of the pfmdr1 gene. For pfATPase6, all the parasites carried the wild-type S769 allele. Sequencing showed no evidence of non-synonymous mutations associated with reduced artemisinin derivative sensitivity in the P. falciparum k13 gene. In conclusion, we found that P. falciparum parasites in Botswana were mostly wild type for the drug resistance markers evaluated. Yet, there was a high rate of a molecular marker associated to reduced sensitivity to lumefantrine. Our results indicate the need for systematic drug efficacy surveillance to complement malaria elimination efforts.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Antimalarials / therapeutic use
  • Artemisinins / therapeutic use
  • Botswana / epidemiology
  • Calcium-Transporting ATPases / genetics*
  • Child
  • Child, Preschool
  • Drug Resistance / genetics*
  • Epidemiological Monitoring
  • Female
  • Gene Dosage
  • Gene Expression
  • Genetic Markers
  • Haplotypes
  • Humans
  • Infant
  • Lumefantrine / therapeutic use
  • Malaria, Falciparum / drug therapy
  • Malaria, Falciparum / epidemiology*
  • Malaria, Falciparum / parasitology
  • Male
  • Membrane Transport Proteins / genetics*
  • Merozoite Surface Protein 1 / genetics
  • Middle Aged
  • Molecular Epidemiology
  • Multidrug Resistance-Associated Proteins / genetics*
  • Plasmodium falciparum / drug effects
  • Plasmodium falciparum / genetics*
  • Plasmodium falciparum / isolation & purification
  • Polymorphism, Genetic
  • Protozoan Proteins / genetics*

Substances

  • ATP6 protein, Plasmodium falciparum
  • Antimalarials
  • Artemisinins
  • Genetic Markers
  • Mdr1 protein, Plasmodium falciparum
  • Membrane Transport Proteins
  • Merozoite Surface Protein 1
  • Multidrug Resistance-Associated Proteins
  • PfCRT protein, Plasmodium falciparum
  • Protozoan Proteins
  • Calcium-Transporting ATPases
  • Lumefantrine