[Aims] The emergence and transnational spread of the “super malaria” strain, the artemisinin resistant Plasmodium falciparum, in the Greater Mekong Subregion (GMS) is a serious threat to malaria elimination in the region. Recently, the Lao government adopted the ambitious goal of malaria elimination by 2030, for which monitoring of artemisinin resistant malaria within the country is indispensable. The objective of present study was to assess the distribution of K13 mutations in Laos, which are associated with artemisinin resistance.
[Methods] We collected 1,151 P. falciparum isolates from five southern provinces in Laos from 2015 through 2016, and analyzed polymorphisms of the K13 gene and two flanking regions.
[Results] Overall, 55.5% possessed non-synonymous K13 mutations. The frequencies of the K13 mutations were heterogeneous in the five southern provinces, but with a clear tendency showing the highest frequency in the south (72.5%) and to a lower degree when moving northward (28.0%). Analysis of the flanking loci demonstrated that these isolates were genetically very close to the resistant lineage originating from western Cambodia, where the first case of artemisinin resistance was reported.
[Conclusions] Artemisinin resistance was observed to be rapidly increasing and spreading northwards through Laos. The Lao government, as well as the international community, should make dedicated efforts to contain the spread of K13 mutations within Laos and in the GMS to avoid its spreading to the world.
[Acknowledgement] Funding Acknowledgements for Lao SATREPS project (JICA/AMED) for Parasitic Diseases.