Surveillance of Antimalarial Resistance Molecular Markers in Imported Malaria Cases in Anhui, China, 2012-2016.

Between 2012 and 2016, over 80% of registered malaria cases in Anhui province were returned from Africa. However, drug-resistance marker polymorphisms in imported cases have not been assessed. This study looked at the distribution of antimalarial-drug resistance by evaluating K13-propeller, , and gene mutations. Fourteen synonymous and 15 nonsynonymous mutations in the K13-propeller gene were detected in samples from nine African countries, yet no candidate and validated K13 resistance mutations were found. The prevalence of K76T and N86Y mutants was 27.7% and 19.9%, respectively. Six different genotypes were found, with CVMNT being the most common (89.2%). The 76- 86 haplotype combination was evaluated in 173 isolates, and the NT genotype was the most prevalent (50.3%). Notably, the prevalence of the N86Y mutation in Africa marked a decline from 31.0% in 2012 to 8.2% in 2016. Our findings suggest that there is no immediate threat to artemisinin efficacy in imported infections returned from Africa to Anhui province. Nevertheless, K76T and N86Y mutations were modestly prevalent, suggesting the presence of chloroquine resistance in these cases. Accordingly, dihydroartemisinin + piperaquine may be a better choice than artesunate + amodiaquine for the treatment of uncomplicated infections in Anhui province. In addition to, artemether-lumefantrine can be introduced as an alternative measure.