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About the Authors:
Veerayuth Kittichai
Roles Formal analysis, Methodology, Writing - original draft, Writing - review & editing
Affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
Cristian Koepfli
Roles Methodology, Validation, Writing - original draft, Writing - review & editing
Affiliation: The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
Wang Nguitragool
Roles Investigation, Supervision, Writing - original draft, Writing - review & editing
Affiliation: Department of Molecular Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
Jetsumon Sattabongkot
Roles Conceptualization, Funding acquisition, Project administration, Resources, Supervision, Writing - original draft, Writing - review & editing
* E-mail: [email protected](JS); [email protected](LC)
Affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
Liwang Cui
Roles Conceptualization, Data curation, Funding acquisition, Project administration, Supervision, Writing - original draft, Writing - review & editing
* E-mail: [email protected](JS); [email protected](LC)
Affiliation: Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
ORCID http://orcid.org/0000-0002-8338-1974Abstract
Background
Plasmodium vivax transmission in Thailand has been substantially reduced over the past 10 years, yet it remains highly endemic along international borders. Understanding the genetic relationship of residual parasite populations can help track the origins of the parasites that are reintroduced into malaria-free regions within the country.
Methodology/Results
A total of 127 P. vivax isolates were genotyped from two western provinces (Tak and Kanchanaburi) and one eastern province (Ubon Ratchathani) of Thailand using 10 microsatellite markers. Genetic diversity was high, but recent clonal expansion was detected in all three provinces. Substantial population structure and genetic differentiation of parasites among provinces suggest limited gene flow among these sites. There was no haplotype sharing among the three sites, and a reduced panel of four microsatellite markers was sufficient to assign the parasites to their provincial origins.
Conclusion/Significance
Significant parasite genetic differentiation between provinces shows successful interruption of parasite spread within Thailand, but high diversity along international borders implies a substantial parasite population size in these regions. The provincial origin of P. vivax cases can be reliably determined by genotyping four microsatellite markers, which should be useful for monitoring parasite reintroduction after malaria elimination.
Author summary
This study presents an updated view of the P. vivax populations along the Thai-Myanmar and the Thai-Cambodian borders. Genotyping...