Artemisinin Resistance at the China-Myanmar Border and Association with Mutations in the K13 Propeller Gene

Abstract

cArtemisinin resistance in Plasmodium falciparum parasites in Southeast Asia is a major concern for malaria control. Its emergence at the China-Myanmar border, where there have been more than 3 decades of artemisinin use, has yet to be investigated. Here, we comprehensively evaluated the potential emergence of artemisinin resistance and antimalarial drug resistance status in P. falciparum using data and parasites from three previous efficacy studies in this region. These efficacy studies of dihydroartemisinin-piperaquine combination and artesunate monotherapy of uncomplicated falciparum malaria in 248 P. falciparum patients showed an overall 28-day adequate clinical and parasitological response of >95% and day 3 parasite-positive rates of 6.3 to 23.1%. Comparison of the 57 K13 sequences (24 and 33 from day 3 parasite-positive and -negative cases, respectively) identified nine point mutations in 38 (66.7%) samples, of which F446I (49.1%) and an N-terminal NN insertion (86.0%) were predominant. K13 propeller mutations collectively, the F446I mutation alone, and the NN insertion all were significantly associated with day 3 parasite positivity. Increased ring-stage survival determined using the ring-stage survival assay (RSA) was highly associated with the K13 mutant genotype. Day 3 parasite-positive isolates had ϳ10 times higher ring survival rates than day 3 parasitenegative isolates. Divergent K13 mutations suggested independent evolution of artemisinin resistance. Taken together, this study confirmed multidrug resistance and emergence of artemisinin resistance in P. falciparum at the China-Myanmar border. RSA and K13 mutations are useful phenotypic and molecular markers for monitoring artemisinin resistance.

Significant Divergence in Sensitivity to Antimalarial Drugs between Neighboring Plasmodium falciparum Populations along the Eastern Border of Myanmar

“…It is important to note that although parasite isolates from the two study sites showed widely different in vitro sensitivities to AS and DHA, these values do not correlate with clinical outcomes. Studies conducted along the China-Myanmar border area have shown overall excellent efficacies of ACTs (25)(26)(27), but slowed parasite clearance and 3-day parasite positivity after ACT treatment were also detected (28,29), indicating possible emergence of artemisinin resistance in this region. For the only known molecular marker of artemisinin resistance, pfk13, earlier data showed that the prevalent K13 mutation in the Shan State is P574L (30), which is correlated with artemisinin resistance (8), whereas the most prevalent K13 point mutation in the Kachin region is F446I (19,28).…”

Plasmodium falciparum Resistance to Artemisinin Derivatives and Piperaquine: A Major Challenge for Malaria Elimination in Cambodia

“…Several molecular epidemiology studies, mostly in southeast Asia, 27,38,[41][42][43][44] China, [45][46][47][48] Indian subcontinent 49,50 and Africa, 27,51-58 investigated the frequency of K13 mutant alleles, their spatial distribution and, in some cases, their association with clinical artemisinin resistance (day 3 positivity rate or parasite clearance half-life). Only 13 independent K13 mutations of about 100 tested were found to be associated with clinical resistance, with evidence of the independent emergence of the same mutation in different areas.…”

Gene mutations in parasitic diseases Part II: Parasite gene mutations

“…The investigators recommended prolonged ART-based combination courses in patients with standard 3-day treatments failures [154] . Several studies were conducted to confirm this link in P. falciparum strains isolated from several Asian countries; Bangladesh [155] , China and Myanmar [156][157][158][159] . On the other hand, its mutation was not prevalent in several African countries; Uganda [151] , Senegal [160] and Mali [161] .…”