Dataset Information

Differential prevalence of Plasmodium infections and cryptic Plasmodium knowlesi malaria in humans in Thailand.

ABSTRACT:

Background

A case of human infection with Plasmodium knowlesi has been recently discovered in Thailand. To investigate the prevalence of this malaria species, a molecular-based survey was performed.

Methods

Blood samples from 1874 patients were tested for Plasmodium species by microscopy and nested polymerase chain reaction. P. knowlesi was characterized by sequencing the merozoite surface protein 1 gene (msp-1).

Results

Of all Plasmodium species identified, P. falciparum, P. vivax, P. malariae, P. ovale, and P. knowlesi contributed 43.52%, 68.08%, 1.37%, 1.03%, and 0.57%, respectively. Mixed-species infections were more common in northwestern and southwestern regions bordering Myanmar (23%-24%) than in eastern and southern areas (3%-5%). In northwestern and southwestern regions, mixed-species infections had a significantly higher prevalence in dry than in rainy seasons (P < .001). P. knowlesi was found in 10 patients, mostly from southern and southwestern areas-9 were coinfected with either P. falciparum or P. vivax. Most of the P. knowlesi Thai isolates were more closely related to isolates from macaques than to isolates from Sarawak patients. The msp-1 sequences of isolates from the same area of endemicity differed and possessed novel sequences, indicating genetic polymorphism in P. knowlesi infecting humans.

Conclusions

This survey highlights the widespread distribution of P. knowlesi in Thailand, albeit at low prevalence and mostly occurring as cryptic infections.

SUBMITTER: Putaporntip C

PROVIDER: S-EPMC8817623 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature

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Publications

Differential prevalence of Plasmodium infections and cryptic Plasmodium knowlesi malaria in humans in Thailand.

Putaporntip Chaturong C Hongsrimuang Thongchai T Seethamchai Sunee S Kobasa Teerayot T Limkittikul Kriengsak K Cui Liwang L Jongwutiwes Somchai S

The Journal of infectious diseases 20090401 8

<h4>Background</h4>A case of human infection with Plasmodium knowlesi has been recently discovered in Thailand. To investigate the prevalence of this malaria species, a molecular-based survey was performed.<h4>Methods</h4>Blood samples from 1874 patients were tested for Plasmodium species by microscopy and nested polymerase chain reaction. P. knowlesi was characterized by sequencing the merozoite surface protein 1 gene (msp-1).<h4>Results</h4>Of all Plasmodium species identified, P. falciparum, ...[more]

PMID: 19284284

Similar Datasets

Project description:BackgroundThailand is committed to eliminating malaria by 2024. From 2013 to 2020, the total number of malaria cases have decreased, from 37,741 to 4474 (an 88.1% reduction). However, infections with Plasmodium knowlesi, a monkey malarial pathogen that can also infect humans, have been increasingly observed. This study focused on the molecular analysis of P. knowlesi parasites causing malaria in Thailand.MethodsUnder Thailand's integrated Drug Efficacy Surveillance (iDES), which includes drug-resistance monitoring as part of routine case-based surveillance and responses, specimens were collected from malaria patients (n = 966) between 2018 and 2020. Thirty-one mono P. knowlesi infections (3.1%), most of which were from eastern and southern Thailand, were observed and confirmed by nested PCR assay and DNA sequencing. To evaluate whether these pathogens were from different lineages, cluster analysis based on seven microsatellite genotyping markers and the merozoite surface protein 1 (pkmsp1) gene was carried out. The P. knowlesi pyrimethamine resistance gene dihydrofolate reductase (pkdhfr) was sequenced and homology modelling was constructed.ResultsThe results of analysing the seven microsatellite markers and pkmsp1 sequence demonstrated that P. knowlesi parasites from eastern Thailand were of the same lineage as those isolated in Cambodia, while the parasites causing malaria in southern Thailand were the same lineage as those isolated from Malaysia. The sequencing results for the pkdhfr genes indicated the presence of two mutations, Arg34Leu and a deletion at position 105. On analysis with homology modelling, the two mutations were not associated with anti-malarial drug resistance.ConclusionsThis report compared the genetic populations of P. knowlesi parasites in Thailand from 2018 to 2020 and have shown similar lineages as those isolated in Cambodia and Malaysia of P. knowlesi infection in Thailand and demonstrated that the P. knowlesi parasites were of the same lineages as those isolated in Cambodia and Malaysia. The parasites were also shown to be sensitive to pyrimethamine.

Dataset Information

Differential prevalence of Plasmodium infections and cryptic Plasmodium knowlesi malaria in humans in Thailand.

Background

Methods

Results

Conclusions

Publications

Differential prevalence of Plasmodium infections and cryptic Plasmodium knowlesi malaria in humans in Thailand.

Similar Datasets

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