Molecular Surveillance of Antimalarial Drug Resistance-Associated Mutations in P. falciparum Imported from Africa into Guangdong Province, China, 2023–2025

Imported falciparum malaria remains an important challenge in China, particularly with the emergence of antimalarial resistance in Africa. This study characterized resistance-associated mutations in pfk13, pfcrt and pfmdr1 by nested PCR and Sanger sequencing of 291 Plasmodium falciparum (P. falciparum) isolates imported from 29 African countries into Guangdong Province during 2023–2025. Sequences were obtained for pfk13 (n = 279), pfcrt (n = 225) and pfmdr1 (n = 235). Four pfk13 variants—C469Y, Y558C, R561H and A675V—were each detected once (0.36%). These isolates originated from East and Central Africa. The wild-type pfk13 haplotype accounted for 98.57% of isolates. For pfcrt, the wild-type MNK haplotype predominated (85.33%), whereas the IET triple-mutant haplotype accounted for 14.22% and was mainly detected in isolates from West and Central Africa. Y184F was the predominant pfmdr1 variant (55.32%), with an annual prevalence of 52.59–60.78%. Other variants included N86Y (3.40%), D1246Y (1.28%), and S163N, T199S and S1217F (0.43% each). The Y184F single-mutant haplotype was most common (51.91%). The imported isolates showed a low prevalence of pfk13 variants, predominance of wild-type pfcrt and frequent pfmdr1 Y184F variants. The detection of several pfk13 variants highlights the need for continued molecular surveillance of antimalarial resistance.