Prevalence of K13 mutation and Day-3 positive parasitaemia in artemisinin-resistant malaria endemic area of Cambodia: a cross-sectional study

Soy Ty Kheang,Say Chy,Dy Soley Lek,Sokkieng Mao,Siv Sovannaroth,Neeraj Kak,Sovann Ek,Sokomar Nguon,Phally Chhun,Didier Menard

doi:10.1186/s12936-017-2024-4

Soy Ty Kheang, Say Chy + Show 8 more

Open Access

https://doi.org/10.1186/s12936-017-2024-4

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Journal: Malaria journal	Publication Date: Sep 13, 2017
Citations: 16	License type: open-access

Affiliation: Cambodia National Malaria Center

Abstract

BackgroundThe presence of artemisinin-resistant malaria parasites was confirmed in western Cambodia in 2009. In 2013, mutations in the propeller domain of the kelch protein K13 was found to be associated with artemisinin resistance. A cross-sectional study was conducted to determine the prevalence of Day-3 parasitaemia, estimate the frequency of k13 molecular marker and assess their relationship in the context of operational research.MethodsBlood smears and filter paper blood spots were collected from febrile patients in Kravanh District, Pursat Province. The blood smears were examined by microscopy, and blood spots by a k13 mutation assay.ResultsData from 92 patients were analysed. Only one was positive for Day-3 parasitaemia. Results of the k13 assay were interpretable for 76 of the 92 samples. The findings were: wild type: 9 (12%), C580Y: 64 (84%), Y493H: 3 (4%). Therefore, despite the high prevalence of k13 mutants (67/76: 88%), only 1 of the 92 patients remained blood smear positive for Plasmodium falciparum on Day-3.ConclusionsThese preliminary findings suggest good potency of artemisinin despite the dominance of k13 mutation in Kravanh, but the result is not necessarily representative of the western part of Cambodia. Further investigation should be made to determine if k13 marker remains useful as a tool for tracking artemisinin resistance and predicting the trend of the efficacy of artemisinin combination therapy once the mutant alleles have been well established in the population.

Highlights

The presence of artemisinin-resistant malaria parasites was confirmed in western Cambodia in 2009
The results indicate a lack of correlation between k13 mutation and the presence of Day-3 parasitaemia
The findings of this study supported the continuation of the use of DHA-PIP. These preliminary findings suggest good potency of artemisinin despite the dominance of k13 mutation in Kravanh. This raises some concern over the relevance of highly prevalent k13 mutation to artemisinin resistance

Summary

Introduction

The presence of artemisinin-resistant malaria parasites was confirmed in western Cambodia in 2009. The Cambodian national therapeutics guidelines earlier adopted DHA-PIP (in principle) as the first line drug for both P. falciparum and Plasmodium vivax in 2010. In both Pursat and Pailin, DHA-PIP efficacy dropped significantly from 2008 to 2010 and prevalence of Day-3 positive parasitaemia increased from 25 to 45% in Pursat and from 8 to 10% in Pailin [4]. TES monitoring of DHA-PIP by the National Center for Parasitology, Entomology and Malaria Control (CNM) found that in 2012, 46% of the patients were Day-3 positive in Pursat and 15% in Tasanh District in Battambang Province, adjacent to Pailin; in 2014, 13% were Day-3 positive in Pursat and 41% in Pailin [5]

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