scholarly journals The Sri Lankan paradox: high genetic diversity in Plasmodium vivax populations despite decreasing levels of malaria transmission – ERRATUM

Parasitology ◽  
2014 ◽  
Vol 141 (7) ◽  
pp. 891-891
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Sri Lankan ◽  
High Genetic Diversity

scholarly journals The Sri Lankan paradox: high genetic diversity in Plasmodium vivax populations despite decreasing levels of malaria transmission

Parasitology ◽  
2014 ◽  
Vol 141 (7) ◽  
pp. 880-890 ◽  
Author(s):  
SHARMINI GUNAWARDENA ◽  
MARCELO U. FERREIRA ◽  
G. M. G. KAPILANANDA ◽  
DYANN F. WIRTH ◽  
NADIRA D. KARUNAWEERA
Keyword(s):  
Genetic Diversity ◽  
Sri Lanka ◽  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Population Size ◽  
Effective Population Size ◽  
Allele Frequency Distribution ◽  
Effective Population ◽  
High Genetic Diversity ◽  
Mode Shift

SUMMARYHere we examined whether the recent dramatic decline in malaria transmission in Sri Lanka led to a major bottleneck in the local Plasmodium vivax population, with a substantial decrease in the effective population size. To this end, we typed 14 highly polymorphic microsatellite markers in 185 P. vivax patient isolates collected from 13 districts in Sri Lanka over a period of 5 years (2003–2007). Overall, we found a high degree of polymorphism, with 184 unique haplotypes (12–46 alleles per locus) and average genetic diversity (expected heterozygosity) of 0·8744. Almost 69% (n = 127) isolates had multiple-clone infections (MCI). Significant spatial and temporal differentiation (FST = 0·04–0·25; P⩽0·0009) between populations was observed. The effective population size was relatively high but showed a decline from 2003–4 to 2006–7 periods (estimated as 45 661 to 22 896 or 10 513 to 7057, depending on the underlying model used). We used three approaches – namely, mode-shift in allele frequency distribution, detection of heterozygote excess and the M-ratio statistics – to test for evidence of a recent population bottleneck but only the low values of M-ratio statistics (ranging between 0·15–0·33, mean 0·26) were suggestive of such a bottleneck. The persistence of high genetic diversity and high proportion of MCI, with little change in effective population size, despite the collapse in demographic population size of P. vivax in Sri Lanka indicates the importance of maintaining stringent control and surveillance measures to prevent resurgence.

scholarly journals Genetic Diversity and Selection at the Plasmodium vivax Apical Membrane Antigen-1 (PvAMA-1) Locus in a Sri Lankan Population

2007 ◽  
Vol 24 (4) ◽  
pp. 939-947 ◽  
Author(s):  
A. M. Gunasekera ◽  
T. Wickramarachchi ◽  
D. E. Neafsey ◽  
I. Ganguli ◽  
L. Perera ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Vivax ◽  
Apical Membrane ◽  
Sri Lankan ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

scholarly journals Genetic diversity, natural selection and haplotype grouping of Plasmodium vivax Duffy-binding protein genes from eastern and western Myanmar borders

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Yubing Hu ◽  
Lin Wang ◽  
Huguette Gaelle Ngassa Mbenda ◽  
Myat Thu Soe ◽  
Chunyun Yu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Natural Selection ◽  
Genetic Differentiation ◽  
Plasmodium Vivax ◽  
Binding Protein ◽  
Duffy Binding Protein ◽  
High Genetic Diversity ◽  
Low Level ◽  
Malaria Epidemiology ◽  
Greater Mekong Subregion

Abstract Background Merozoite proteins of the malaria parasites involved in the invasion of red blood cells are selected by host immunity and their diversity is greatly influenced by changes in malaria epidemiology. In the Greater Mekong Subregion (GMS), malaria transmission is concentrated along the international borders and there have been major changes in malaria epidemiology with Plasmodium vivax becoming the dominant species in many regions. Here, we aimed to evaluate the genetic diversity of P. vivax Duffy-binding protein gene domain II (pvdbp-II) in isolates from the eastern and western borders of Myanmar, and compared it with that from global P. vivax populations. Methods pvdbp-II sequences were obtained from 85 and 82 clinical P. vivax isolates from the eastern and western Myanmar borders, respectively. In addition, 504 pvdbp-II sequences from nine P. vivax populations of the world were retrieved from GenBank and used for comparative analysis of genetic diversity, recombination and population structure of the parasite population. Results The nucleotide diversity of the pvdbp-II sequences from the Myanmar border parasite isolates was not uniform, with the highest diversity located between nucleotides 1078 and 1332. Western Myanmar isolates had a unique R391C mutation. Evidence of positive natural selection was detected in pvdbp-II gene in P. vivax isolates from the eastern Myanmar area. P. vivax parasite populations in the GMS, including those from the eastern, western, and central Myanmar as well as Thailand showed low-level genetic differentiation (FST, 0.000–0.099). Population genetic structure analysis of the pvdbp-II sequences showed a division of the GMS populations into four genetic clusters. A total of 60 PvDBP-II haplotypes were identified in 210 sequences from the GMS populations. Among the epitopes in PvDBP-II, high genetic diversity was found in epitopes 45 (379-SIFGT(D/G)(E/K)(K/N)AQQ(R/H)(R/C)KQ-393, π = 0.029) and Ia (416-G(N/K)F(I/M)WICK(L/I)-424], Ib [482-KSYD(Q/E)WITR-490, π = 0.028) in P. vivax populations from the eastern and western borders of Myanmar. Conclusions The pvdbp-II gene is genetically diverse in the eastern and western Myanmar border P. vivax populations. Positive natural selection and recombination occurred in pvdbp-II gene. Low-level genetic differentiation was identified, suggesting extensive gene flow of the P. vivax populations in the GMS. These results can help understand the evolution of the P. vivax populations in the course of regional malaria elimination and guide the design of PvDBP-II-based vaccine.

scholarly journals Chloroquine efficacy for Plasmodium vivax in Myanmar in populations with high genetic diversity and moderate parasite gene flow

2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Myo Win Htun ◽  
Nan Cho Nwe Mon ◽  
Khin Myo Aye ◽  
Chan Myae Hlaing ◽  
Myat Phone Kyaw ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Plasmodium Vivax ◽  
High Genetic Diversity

scholarly journals Parasite genetic diversity reflects continued residual malaria transmission in Vhembe District, a hotspot in the Limpopo Province of South Africa

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Hazel B. Gwarinda ◽  
Sofonias K. Tessema ◽  
Jaishree Raman ◽  
Bryan Greenhouse ◽  
Lyn-Marié Birkholtz
Keyword(s):  
South Africa ◽  
Genetic Diversity ◽  
Malaria Transmission ◽  
Limpopo Province ◽  
Parasite Population ◽  
High Genetic Diversity ◽  
Management Interventions ◽  
Imported Cases ◽  
Study Sites ◽  
Vhembe District

Abstract Background South Africa aims to eliminate malaria transmission by 2023. However, despite sustained vector control efforts and case management interventions, the Vhembe District remains a malaria transmission hotspot. To better understand Plasmodium falciparum transmission dynamics in the area, this study characterized the genetic diversity of parasites circulating within the Vhembe District. Methods A total of 1153 falciparum-positive rapid diagnostic tests (RDTs) were randomly collected from seven clinics within the district, over three consecutive years (2016, 2017 and 2018) during the wet and dry malaria transmission seasons. Using 26 neutral microsatellite markers, differences in genetic diversity were described using a multiparameter scale of multiplicity of infection (MOI), inbreeding metric (Fws), number of unique alleles (A), expected heterozygosity (He), multilocus linkage disequilibrium (LD) and genetic differentiation, and were associated with temporal and geospatial variances. Results A total of 747 (65%) samples were successfully genotyped. Moderate to high genetic diversity (mean He = 0.74 ± 0.03) was observed in the parasite population. This was ascribed to high allelic richness (mean A = 12.2 ± 1.2). The majority of samples (99%) had unique multi-locus genotypes, indicating high genetic diversity in the sample set. Complex infections were observed in 66% of samples (mean MOI = 2.13 ± 0.04), with 33% of infections showing high within-host diversity as described by the Fws metric. Low, but significant LD (standardised index of association, ISA = 0.08, P < 0.001) was observed that indicates recombination of distinct clones. Limited impact of temporal (FST range − 0.00005 to 0.0003) and spatial (FST = − 0.028 to 0.023) variation on genetic diversity existed during the sampling timeframe and study sites respectively. Conclusions Consistent with the Vhembe District’s classification as a ‘high’ transmission setting within South Africa, P. falciparum diversity in the area was moderate to high and complex. This study showed that genetic diversity within the parasite population reflects the continued residual transmission observed in the Vhembe District. This data can be used as a reference point for the assessment of the effectiveness of on-going interventions over time, the identification of imported cases and/or outbreaks, as well as monitoring for the potential spread of anti-malarial drug resistance.

scholarly journals Parasite genetic diversity reflects continued residual malaria transmission in Vhembe District, a hotspot in the Limpopo Province of South Africa

2021 ◽  
Author(s):  
Hazel B. Gwarinda ◽  
Sofonias K. Tessema ◽  
Jaishree Raman ◽  
Bryan Greenhouse ◽  
Lyn-Marie Birkholtz
Keyword(s):  
South Africa ◽  
Genetic Diversity ◽  
Malaria Transmission ◽  
Limpopo Province ◽  
Parasite Population ◽  
High Genetic Diversity ◽  
Management Interventions ◽  
Imported Cases ◽  
Study Sites ◽  
Vhembe District

Abstract Background: South Africa aims to eliminate malaria transmission by 2023. However, despite sustained vector control efforts and case management interventions, the Vhembe District remains a malaria transmission hotspot. To better understand Plasmodium falciparum transmission dynamics in the area, this study characterised the genetic diversity of parasites circulating within the Vhembe District.Methods: A total of 1153 falciparum-positive rapid diagnostic tests (RDTs) were randomly collected from seven clinics within the district, over three consecutive years (2016, 2017 and 2018) during the wet and dry malaria transmission seasons. Using 26 neutral microsatellite markers, differences in genetic diversity were described using a multiparameter scale of multiplicity of infection (MOI), inbreeding metric (Fws), number of unique alleles (A), expected heterozygosity (He), multilocus linkage disequilibrium (LD) and genetic differentiation, and were associated with temporal and geospatial variances. Results: A total of 747 (65%) samples were successfully genotyped. Moderate to high genetic diversity (mean He = 0.74 ± 0.03) was observed in the parasite population. This was ascribed to high allelic richness (mean A = 12.2 ± 1.2). The majority of samples (99%) had unique multi-locus genotypes, indicating high genetic diversity in the sample set. Complex infections were observed in 66% of samples (mean MOI = 2.13 ± 0.04), with 33% of infections showing high within-host diversity as described by the Fws metric. Low, but significant LD (standardised index of association, ISA = 0.08, P < 0.001) was observed that indicates recombination of distinct clones. Limited impact of temporal (FST range -0.00005 to 0.0003) and spatial (FST = –0.028 to 0.023) variation on genetic diversity existed during the sampling timeframe and study sites respectively. Conclusion: Consistent with the Vhembe District’s classification as a 'high' transmission setting within South Africa, P. falciparum diversity in the area was moderate to high and complex. This study showed that genetic diversity within the parasite population reflects the continued residual transmission observed in the Vhembe District. This data can be used as a reference point for the assessment of the effectiveness of on-going interventions over time, the identification of imported cases and/or outbreaks, as well as monitoring for the potential spread of antimalarial drug resistance.

scholarly journals Parasite Genetic Diversity Reflects Continued Residual Malaria Transmission in Vhembe District, A Hotspot in the Limpopo Province of South Africa

2020 ◽  
Author(s):  
Hazel B. Gwarinda ◽  
Sofonias K. Tessema ◽  
Jaishree Raman ◽  
Bryan Greenhouse ◽  
Lyn-Marié Birkholtz
Keyword(s):  
South Africa ◽  
Genetic Diversity ◽  
Malaria Transmission ◽  
Limpopo Province ◽  
Parasite Population ◽  
High Genetic Diversity ◽  
Host Diversity ◽  
Management Interventions ◽  
Study Sites ◽  
Vhembe District

Abstract Background: South Africa aims to eliminate malaria transmission by 2023. However, despite sustained vector control efforts and case management interventions, the Vhembe District in the Limpopo Province remains a malaria transmission hotspot. To better understand Plasmodium falciparum transmission dynamics in the area, this study characterised the genetic diversity of parasites circulating within the Vhembe District.Methods: A total of 1153 falciparum-positive rapid diagnostic tests (RDTs) were randomly collected from seven clinics within the district, over three consecutive years (2016, 2017 and 2018) during the wet and dry malaria transmission seasons. Parasite genomic material was isolated from the RDTs and parasite genetic diversity was characterised using 26 neutral microsatellite markers. Differences in genetic diversity were described using a multiparameter scale of multiplicity of infection (MOI), within-host diversity metric (Fws), number of unique alleles (A), expected heterozygosity (He), multilocus linkage disequilibrium (LD) and genetic differentiation (Wright's F-statistic, FST), and were associated with temporal and geospatial variances. Results: A total of 747 (65%) samples were successfully genotyped. High genetic diversity (mean heterozygosity, He = 0.74 ± 0.03) was observed in the parasite population. This was ascribed to high allelic richness (mean A = 12.2 ± 1.2). The majority of samples (99%) had unique multi-locus genotypes, indicating high genetic diversity in the sample set. Complex infections were observed in 66% of samples (mean MOI = 2.13 ± 0.04), with 33% of infections showing high within-host diversity as described by the Fws metric. Low, but significant LD (standardised index of association, ISA = 0.08, P < 0.001) was observed that indicates recombination of distinct clones. Limited impact of temporal (FST range -0.00005 to 0.0003) and spatial (FST = –0.028 to 0.023) variation on genetic diversity existed during the sampling timeframe and study sites respectively. Conclusion: Consistent with the Vhembe District’s classification as a 'high' transmission setting within South Africa, P. falciparum diversity in the area was high and complex. This study showed that genetic diversity within the parasite population reflects the continued residual transmission observed in the Vhembe District. This finding, together with continued surveillance of P. falciparum genetic diversity in South Africa, may influence future intervention strategies by targeting the parasite to decrease transmission intensity for the country to achieve its elimination goals.

Genetic diversity of Plasmodium vivax over time and space: a community-based study in rural Amazonia

Parasitology ◽  
2014 ◽  
Vol 142 (2) ◽  
pp. 374-384 ◽  
Author(s):  
CAMILLA L. BATISTA ◽  
SUSANA BARBOSA ◽  
MELISSA DA SILVA BASTOS ◽  
SUSANA ARIANE S. VIANA ◽  
MARCELO U. FERREIRA
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Vivax ◽  
Amazon Basin ◽  
Spatial Clustering ◽  
Malaria Incidence ◽  
Time And Space ◽  
Community Based ◽  
High Genetic Diversity ◽  
Early Phases

SUMMARYTo examine how community-level genetic diversity of the malaria parasite Plasmodium vivax varies across time and space, we investigated the dynamics of parasite polymorphisms during the early phases of occupation of a frontier settlement in the Amazon Basin of Brazil. Microsatellite characterization of 84 isolates of P. vivax sampled over 3 years revealed a moderate-to-high genetic diversity (mean expected heterozygosity, 0·699), with a large proportion (78·5%) of multiple-clone infections (MCI), but also a strong multilocus linkage disequilibrium (LD) consistent with rare outcrossing. Little temporal and no spatial clustering was observed in the distribution of parasite haplotypes. A single microsatellite haplotype was shared by 3 parasites collected during an outbreak; all other 81 haplotypes were recovered only once. The lowest parasite diversity, with the smallest proportion of MCI and the strongest LD, was observed at the time of the outbreak, providing a clear example of epidemic population structure in a human pathogen. Population genetic parameters returned to pre-outbreak values during last 2 years of study, despite the concomitant decline in malaria incidence. We suggest that parasite genotyping can be useful for tracking the spread of new parasite strains associated with outbreaks in areas approaching malaria elimination.

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