Case Report: The First Case of Genotypically Confirmed Plasmodium falciparum Kelch 13 Propeller Mutation in Sri Lanka and Its Implications on the Elimination Status of Malaria.

This case report discusses recrudescence of imported Plasmodium falciparum malaria, in the presence of P. falciparum Kelch13 (PfK13) propeller mutation, in a patient diagnosed and fully treated with artemether-lumefantrine under direct observation in Sri Lanka. This patient presented with a history of 5 days of fever following his arrival from the Democratic Republic of Congo (DRC). He had visited Rwanda 1 week before arrival to Sri Lanka. Treatment was commenced with artemisinin-based combination therapy, artemether-lumefantrine, which is the first-line drug recommended for uncomplicated falciparum malaria. Blood smears were negative for parasites by the third day of treatment. Approximately 2 weeks later, he developed fever again and was diagnosed as having a recrudescence of falciparum malaria. He was treated and responded to the second-line antimalarial dihydroartemisinin-piperaquine. Molecular testing of blood taken from the first infection revealed the presence of amino acid substitutions K189T and R561H within the PfK13 gene. R561H mutation is associated with delayed parasite clearance in Southeast Asia. Although seldom reported from DRC, an emergence and clonal expansion of parasites harboring R561H allele has been reported from Rwanda recently; thus, it is likely that this patient may have got the infection from Rwanda. Sri Lanka eliminated malaria in 2016. However, in the backdrop of continuing imported malaria cases, early diagnosis and prompt treatment is essential to prevent the re-establishment of the disease.