Dataset Information

Recent increase of genetic diversity in Plasmodium vivax population in the Republic of Korea.

ABSTRACT:

Background

The reemergence of Plasmodium vivax in South Korea since 1993 represents a serious public health concern. Despite the importance in understanding genetic diversity for control strategies, however, studies remain inconclusive with the general premise that due to low rate of malaria transmission, there is generally low genetic diversity with very few strains involved. In this study, the genetic diversity and population structure of P. vivax in South Korea were explored by analysing microsatellite polymorphism.

Methods

Sequences for 13 microsatellite loci distributed across the twelve chromosomes of P. vivax were obtained from 58 South Korean isolates collected during two sampling periods, namely 1997-2000 and 2007. The sequences were used for the analysis of expected heterozygosity and multilocus genotype diversity. Population structure was evaluated using STRUCTURE version 2.3.2. Linkage disequilibrium was also analysed to investigate the extent of outbreeding in the P. vivax population.

Results

Mean expected heterozygosity significantly increased from 0.382 in 1997-2000 to 0.545 in 2007 (P < 0.05). The number of multilocus genotypes was 7 and 27; and genotype diversity was statistically significant (P < 0.01) at 0.661 and 0.995 in 1997-2000 and 2007, respectively. Analysis by STRUCTURE showed a more complex population structure in 2007 than in 1997-2000. Linkage disequilibrium between 13 microsatellites, although significant in both time points, was notably lower in 2007.

Conclusions

The present microsatellite analysis clearly showed recent increase of genetic diversity and recent relaxation of the strong population structure observed in 1997-2000. These results suggest that multiple genotypes not present previously recently migrated into South Korea, accompanied by substantial outbreeding between different genotypes.

SUBMITTER: Honma H

PROVIDER: S-EPMC3176257 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Recent increase of genetic diversity in Plasmodium vivax population in the Republic of Korea.

Honma Hajime H Kim Jung-Yeon JY Palacpac Nirianne M Q NM Mita Toshihiro T Lee Wonja W Horii Toshihiro T Tanabe Kazuyuki K

Malaria journal 20110907

<h4>Background</h4>The reemergence of Plasmodium vivax in South Korea since 1993 represents a serious public health concern. Despite the importance in understanding genetic diversity for control strategies, however, studies remain inconclusive with the general premise that due to low rate of malaria transmission, there is generally low genetic diversity with very few strains involved. In this study, the genetic diversity and population structure of P. vivax in South Korea were explored by analys ...[more]

PMID: 21899730

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Project description:In Central China the declining incidence of Plasmodium vivax has been interrupted by epidemic expansions and imported cases. The impact of these changes on the local parasite population, and concurrent risks of future resurgence, was assessed.Plasmodium vivax isolates collected from Anhui and Jiangsu provinces, Central China between 2007 and 2010 were genotyped using capillary electrophoresis at seven polymorphic short tandem repeat markers. Spatial and temporal analyses of within-host and population diversity, population structure, and relatedness were conducted on these isolates.Polyclonal infections were infrequent in the 94 isolates from Anhui (4%) and 25 from Jiangsu (12%), with a trend for increasing frequency from 2008 to 2010 (2 to 19%) when combined. Population diversity was high in both provinces and across the years tested (H(E)?=?0.8 - 0.85). Differentiation between Anhui and Jiangsu was modest (F'(ST)?=?0.1). Several clusters of isolates with identical multi-locus haplotypes were observed across both Anhui and Jiangsu. Linkage disequilibrium was strong in both populations and in each year tested (I(A)(S)?=?0.2 - 0.4), but declined two- to four-fold when identical haplotypes were accounted for, indicative of occasional epidemic transmission dynamics. None of five imported isolates shared identical haplotypes to any of the central Chinese isolates.The population genetic structure of P. vivax in Central China highlights unstable transmission, with limited barriers to gene flow between the central provinces. Despite low endemicity, population diversity remained high, but the reservoirs sustaining this diversity remain unclear. The challenge of imported cases and risks of resurgence emphasize the need for continued surveillance to detect early warning signals. Although parasite genotyping has potential to inform the management of outbreaks, further studies are required to identify suitable marker panels for resolving local from imported P. vivax isolates.

Project description:BACKGROUND: In order to control malaria, it is important to understand the genetic structure of the parasites in each endemic area. Plasmodium vivax is widely distributed in the tropical to temperate regions of Asia and South America, but effective strategies for its elimination have yet to be designed. In South Korea, for example, indigenous vivax malaria was eliminated by the late 1970s, but re-emerged from 1993. We estimated the population structure and temporal dynamics of transmission of P. vivax in South Korea using microsatellite DNA markers. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 255 South Korean P. vivax isolates collected from 1994 to 2008, based on 10 highly polymorphic microsatellite DNA loci of the P. vivax genome. Allelic data were obtained for the 87 isolates and their microsatellite haplotypes were determined based on a combination of allelic data of the loci. In total, 40 haplotypes were observed. There were two predominant haplotypes: H16 and H25. H16 was observed in 9 isolates (10%) from 1996 to 2005, and H25 in 27 (31%) from 1995 to 2003. These results suggested that the recombination rate of P. vivax in South Korea, a temperate country, was lower than in tropical areas where identical haplotypes were rarely seen in the following year. Next, we estimated the relationships among the 40 haplotypes by eBURST analysis. Two major groups were found: one composed of 36 isolates (41%) including H25; the other of 20 isolates (23%) including H16. Despite the low recombination rate, other new haplotypes that are genetically distinct from the 2 groups have also been observed since 1997 (H27). CONCLUSIONS/SIGNIFICANCE: These results suggested a continual introduction of P. vivax from other population sources, probably North Korea. Molecular epidemiology using microsatellite DNA of the P. vivax population is effective for assessing the population structure and transmission dynamics of the parasites--information that can assist in the elimination of vivax malaria in endemic areas.

Dataset Information

Recent increase of genetic diversity in Plasmodium vivax population in the Republic of Korea.

Background

Methods

Results

Conclusions

Publications

Recent increase of genetic diversity in Plasmodium vivax population in the Republic of Korea.

Similar Datasets

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