Continued Sensitivity of to Artemisinin in Guyana, With Absence of Kelch Propeller Domain Mutant Alleles.

Because of concerns about possible emergence of artemisinin resistance strains of in mining areas of the interior of Guyana, a 7-day artesunate trial was conducted from March to December 2014. The day-3 parasite clearance rate, the efficacy of artesunate at day 28, and polymorphism of Kelch 13 ()-the marker of artemisinin resistance-were assessed. The study confirmed the continued sensitivity of to artemisinin.

Independent Emergence of the Plasmodium falciparum Kelch Propeller Domain Mutant Allele C580Y in Guyana.

Suspected artemisinin resistance in Plasmodium falciparum can be explored by examining polymorphisms in the Kelch (PfK13) propeller domain. Sequencing of PfK13 and other gene resistance markers was performed on 98 samples from Guyana. Five of these samples carried the C580Y allele in the PfK13 propeller domain, with flanking microsatellite profiles different from those observed in Southeast Asia.