Identification of the PfK13 mutations R561H and P441L in Democratic Republic of Congo (DRC).

BACKGROUND: Partial artemisinin resistance, mediated by P. falciparum K13 (PfK13) mutations, has been confirmed in certain areas of East Africa which are historically associated with high-level antimalarial resistance. DRC borders these areas in the East.

OBJECTIVES: To determine the prevalence of resistance markers in six national malaria control programme (NMCP) surveillance sites; Boende, Kabondo, Kapolowe, Kimpese, Mikalayi and Rutshuru.

METHODS: The SNPs in P. falciparum genes PfK13, Pfdhfr, Pfdhps, Pfmdr1 and Pfcrt were assessed using targeted NGS of isolates collected at enrolment in therapeutic efficacy studies.

RESULTS: PfK13 SNPs were detected in two samples; in Kabondo (R561H) and in Rutshuru (P441L), both areas near Uganda and Rwanda. The Pfdhps ISGEGA haplotype, associated with reduced SP chemoprevention efficacy, ranged from 0.8% in Mikalayi (central DRC) to 42.2% in Rutshuru (East DRC).

CONCLUSIONS: R561H and P441L observed in eastern DRC are a concern, as they are associated with delayed ACT-clearance and candidate marker of resistance, respectively. This is consistent with previous observations of shared drug resistance profiles in parasites of that region with bordering areas of Rwanda and Uganda. The likely circulation of parasites has important implications for the ongoing surveillance of partial artemisinin-resistant P. falciparum and for future efforts to mitigate its dispersal.