Molecular surveillance of malaria in the Central Highlands, Vietnam

Võ, Tuấn Cường; Lê, Hương Giang; Kang, Jung‐Mi; Naw, Haung; Fan, Chia-Kwung; Trinh, Nguyên Thị Minh; Quang, Huynh Hong; Na, Byoung-Kuk

doi:10.1016/j.parint.2021.102374

Cited by 13 publications

(13 citation statements)

References 36 publications

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“…This is much less clear in the Americas, where some of the regions with high incidence of malaria are still within the low to medium transmission levels and accordingly show low diversity of the parasite populations [24]. Some of the most widely used markers are two genes that encode the merozoite surface proteins of P. falciparum (pfmsp-1 and pfmsp-2) [17,[25][26][27][28][29]. These markers are very informative due to their high rate of size and sequence polymorphisms, due in part to their tendency to recombine during the sexual phase of the cycle [30,31].…”

Section: Introductionmentioning

confidence: 99%

Evidence of a Recent Bottleneck in Plasmodium falciparum Populations on the Honduran–Nicaraguan Border

et al. 2021

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The countries of Central America and the island of Hispaniola have set the goal of eliminating malaria in less than a decade. Although efforts to reduce the malaria burden in the region have been successful, there has been an alarming increase in cases in the Nicaraguan Moskitia since 2014. The continuous decrease in cases between 2000 and 2014, followed by a rapid expansion from 2015 to the present, has generated a potential bottleneck effect in the populations of Plasmodium spp. Consequently, this study aimed to evaluate the genetic diversity of P. falciparum and the decrease in allelic richness in this population. The polymorphic regions of the pfmsp-1 and pfmsp-2 genes of patients with falciparum malaria from Honduras and Nicaragua were analyzed using nested PCR and sequencing. Most of the samples were classified into the K1 allelic subfamily of the pfmsp-1 gene and into the 3D7 subfamily of the pfmsp-2 gene. Despite the low genetic diversity found, more than half of the samples presented a polyclonal K1/RO33 haplotype. No sequence polymorphisms were found within each allelic subfamily. This study describes a notable decrease in the genetic diversity of P. falciparum in the Moskitia region after a bottleneck phenomenon. These results will be useful for future epidemiological investigations and the monitoring of malaria transmission in Central America.

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Section: Introductionmentioning

confidence: 99%

Evidence of a Recent Bottleneck in Plasmodium falciparum Populations on the Honduran–Nicaraguan Border

et al. 2021

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“…The malaria burden in Vietnam has remarkably reduced in the recent years. However, the Central Highlands remains a major malaria transmission area [ 20 ]. The increasing prevalence and high genetic heterogenicity of P. vivax in the Central Highlands is also becoming a major concern in current efforts to control and eliminate malaria in the endemic areas [ 17 ].…”

Section: Discussionmentioning

confidence: 99%

“…The blood samples were obtained by finger pricks from malaria patients residing in four provinces (Dak Lak, Dak Nong, Gia Lai, and Kon Tum) in the Central Highlands, Vietnam, in 2018 and 2019 (Supplement File S1: Figure S1 ). Information on the blood samples and molecular diagnosis of the P. vivax infection were described in our previous report [ 20 ]. The Ministry of Health, Institutional Review Board of the Institute of Malariology, Parasitology and Entomology Quy Nhon, Vietnam (368/VSR-LSDT) reviewed and approved the study protocols, and informed consent was obtained from all participants before blood collection.…”

Section: Methodsmentioning

confidence: 99%

Genetic Diversity of Circumsporozoite Surface Protein of Plasmodium vivax from the Central Highlands, Vietnam

et al. 2022

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The circumsporozoite surface protein of Plasmodium vivax (PvCSP) plays a critical role in parasite biology. It has been extensively studied as a leading vivax-malaria-vaccine candidate. In this study, the genetic polymorphism and natural selection of pvcsp in P. vivax isolates collected from the Central Highlands, Vietnam were analyzed to understand the genetic structure of the parasite circulating in the endemic area and to provide baseline information for effective vaccine development based on the protein. Only two major alleles, VK210 and VK247, were detected in Vietnamese pvcsp, with VK247 being the predominant one. The N-terminal and C-terminal regions of Vietnamese VK210 and VK247 variants showed a low genetic diversity. Amino acid substitutions, insertions of a single amino acid or octapeptide (ANKKAEDA in VK210 and ANKKAGDA in VK247), and tetrapeptide repeat motifs (GGNA) were the main factors generating genetic diversity in the two regions of the Vietnamese VK210 and VK247 variants. Interestingly, these two regions of Vietnamese pvcsp displayed a unique natural selection pressure distinct from global pvcsp, particularly with the neighboring Southeast Asian pvcsp population. Meanwhile, the central repeat region (CRR) in both the VK210 and VK247 variants showed a high degree of polymorphic characters, caused by varying numbers, types, and combinations of peptide repeat motifs (PRMs) in Vietnamese pvcsp. Highly complicated polymorphic patterns of the CRR were also detected in global pvcsp. These results expand our understanding of the genetic structure of Vietnamese pvcsp and the population dynamics of P. vivax in the Central Highlands, Vietnam.

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“…Blood samples were collected from malaria patients who were infected with Plasmodium falciparum in Dak Lak Province, Central Highlands, Vietnam, in 2019 [ 31 ] ( Figure 1 ). Malaria infection was initially diagnosed using microscopic examinations for thick and thin blood smears.…”

Section: Methodsmentioning

confidence: 99%

“…The National Malaria Control and Elimination Program (NMCEP) of Vietnam has aimed for malaria elimination in the country by 2030 [ 28 ]. However, the Central Highlands of Vietnam, which are forests or forest edges, is still a high malaria risk area [ 29 ], and P. falciparum is a dominant species circulating in the Central Highlands [ 30 , 31 ]. Concerns for the emergence and spread of antimalarial drug-resistant parasites also have increased [ 32 , 33 , 34 , 35 ].…”

Section: Introductionmentioning

confidence: 99%

Genetic Polymorphism and Natural Selection of Apical Membrane Antigen-1 in Plasmodium falciparum Isolates from Vietnam

Kang

Lê

Võ

et al. 2021

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Apical membrane antigen-1 of Plasmodium falciparum (PfAMA-1) is a leading malaria vaccine candidate antigen. However, the genetic diversity of pfama-1 and associated antigenic variation in global P. falciparum field isolates are major hurdles to the design of an efficacious vaccine formulated with this antigen. Here, we analyzed the genetic structure and the natural selection of pfama-1 in the P. falciparum population of Vietnam. A total of 37 distinct haplotypes were found in 131 P. falciparum Vietnamese isolates. Most amino acid changes detected in Vietnamese pfama-1 were localized in the ectodomain, domains I, II, and III. Overall patterns of major amino acid changes in Vietnamese pfama-1 were similar to those of global pfama-1, but the frequencies of the amino acid changes slightly differed by country. Novel amino acid changes were also identified in Vietnamese pfama-1. Vietnamese pfama-1 revealed relatively lower genetic diversity than currently analyzed pfama-1 in other geographical regions, and suggested a distinct genetic differentiation pattern. Evidence for natural selection was detected in Vietnamese pfama-1, but it showed purifying selection unlike the global pfama-1 analyzed so far. Recombination events were also found in Vietnamese pfama-1. Major amino acid changes that were commonly identified in global pfama-1 were mainly localized to predicted B-cell epitopes, RBC-binding sites, and IUR regions. These results provide important information for understanding the genetic nature of the Vietnamese pfama-1 population, and have significant implications for the design of a vaccine based on PfAMA-1.

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Molecular surveillance of malaria in the Central Highlands, Vietnam

Cited by 13 publications

References 36 publications

Evidence of a Recent Bottleneck in Plasmodium falciparum Populations on the Honduran–Nicaraguan Border

Evidence of a Recent Bottleneck in Plasmodium falciparum Populations on the Honduran–Nicaraguan Border

Genetic Diversity of Circumsporozoite Surface Protein of Plasmodium vivax from the Central Highlands, Vietnam

Genetic Polymorphism and Natural Selection of Apical Membrane Antigen-1 in Plasmodium falciparum Isolates from Vietnam

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