Prevalence of Plasmodium species in asymptomatic individuals in North-Eastern South Africa: 2018 - 2019

Authors

  • M Munzhedzi Department of Biochemistry and Microbiology, University of Venda, Thohoyandou, South Africa; SAMRC-University of Venda Antimicrobial Resistance and Global Health Research Unit, Thohoyandou, South Africa https://orcid.org/0000-0003-1082-0881
  • J L Guler Department of Biology, University of Virginia, Charlottesville, Va, USA https://orcid.org/0000-0001-6301-4563
  • S Krivacsy Department of Public Health Sciences, University of Virginia, Charlottesville, Va, USA
  • P Shifflett Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Va, USA https://orcid.org/0009-0005-5638-2647
  • D J Operario Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Va, USA https://orcid.org/0000-0002-3815-9311
  • R Dillingham Center for Global Health Equity, Department of Infectious Diseases and International Health, University of Virginia, Charlottesville, Va, USA https://orcid.org/0000-0001-9748-1215
  • E T R McQuade Department of Epidemiology, Emory University, Atlanta, Ga, USA https://orcid.org/0000-0002-4942-3747
  • P O Bessong SAMRC-University of Venda Antimicrobial Resistance and Global Health Research Unit, Thohoyandou, South Africa; Center for Global Health Equity, University of Virginia, Charlottesville, Va, USA; School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa https://orcid.org/0000-0003-0561-272X

DOI:

https://doi.org/10.7196/SAMJ.2025.v115i8.2273

Keywords:

Asymptomatic Plasmodium infections; High Resolution Melt analysis; Pfk13

Abstract

Background. Asymptomatic Plasmodium infections in endemic areas pose a challenge to malaria prevention and control strategies. The Ha-Lambani area in Vhembe district, Limpopo Province, South Africa, experiences periodic malaria outbreaks, possibly influenced by asymptomatic Plasmodium infections. In addition, the identification and monitoring of the Plasmodium falciparum Kelch 13 (Pfk13) gene associated with artemisinin resistance are crucial for understanding the emergence and spread of drug-resistant malaria in endemic areas.

Objective. To determine the prevalence of asymptomatic Plasmodium infection and Pfk13 gene polymorphisms in the Ha-Lambani area in the absence of a malaria outbreak.

Methods. Finger-prick dried blood spots from 985 asymptomatic individuals were collected from November 2018 to May 2019. A P. falciparum-specific rapid diagnostic test (RDT) was used to test for Plasmodium infection. High-resolution melt (HRM) analysis was used to test for P. falciparum, P. ovale, P. vivax and P. malariae. The prevalence of Plasmodium infection was determined by the proportion of positive cases detected by at least one of the tests. The Pfk13 gene was amplified from P. falciparum-positive samples, sequenced by Sanger and Illumina next-generation sequencing (NGS) and analysed for genetic diversity and resistance mutations to artemisinin.

Results. A prevalence of 7.1% (70/985; 95% confidence interval (CI): 0.054 - 0.087) of Plasmodium infection was observed. The dominant species was P. ovale (57.14%; n=40), followed by P. falciparum (37.1%; n=26), P. malariae (1.43%) and P. vivax (1.43%). Mixed infections were P. falciparum/P. ovale (2.9%). Plasmodium infections differed significantly by village (p<0.01). The Pfk13 gene was amplified from 5/30 (95% CI: 0.03 - 0.29). Analysis of NGS reads revealed 57 single nucleotide polymorphisms (SNPs) across the Pfk13 gene (≥20% minority level). Up to 70.1% (39/57; 95% CI: 0.59 - 0.83) of the SNPs were non-synonymous and none was previously associated with artemisinin resistance. However, novel SNPs (H719Q, P701T, M472I, I526R and P443S) were detected in the propeller domain.

Conclusion. A relatively high asymptomatic Plasmodium infection prevalence was observed in the study area, with P. ovale being the most prevalent species. Therefore, P. ovale infections may be missed with the Plasmodium RDT. R21 and RTS,S vaccines may not offer protection against P. ovale in the study area. Further research is needed to link asymptomatic infections in the study area and the periodic malaria outbreaks, and to determine the significance of the novel SNP in the Pfk13 gene.

Author Biographies

  • M Munzhedzi, Department of Biochemistry and Microbiology, University of Venda, Thohoyandou, South Africa; SAMRC-University of Venda Antimicrobial Resistance and Global Health Research Unit, Thohoyandou, South Africa

    Dr Mukhethwa Munzhedzi is a researcher in Microbiology at the University of Venda. Her research interests include community Malaria studies, cholerae and SARs Cov-2 surveillance, and antimicrobial resistance.

  • J L Guler, Department of Biology, University of Virginia, Charlottesville, Va, USA

    Associate Professor of Biology

  • S Krivacsy, Department of Public Health Sciences, University of Virginia, Charlottesville, Va, USA

    Sara Krivacsy received her BA in Global Public Health from the University of Virginia in 2020 and is currently pursuing her medical degree as a member of the Albert Einstein College of Medicine Class of 2025.

  • D J Operario, Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Va, USA

    At time of this work, Dr. Darwin J. Operario was a Senior Scientist at the University of Virginia Health System’s Division of Infectious Diseases and International Health where he specialized in the development molecular diagnostic assays and in their deployment to international sites for research and laboratory capacity building. 

  • R Dillingham, Center for Global Health Equity, Department of Infectious Diseases and International Health, University of Virginia, Charlottesville, Va, USA

    Dr Rebecca Dillingham (MD/MPH) is an infectious disease clinician-researcher specializing in HIV and HCV care and care systems.  she has collaborated closely with the Virginia (USA) Department of Health (VDH) to design and implement innovative HIV care system interventions, especially mHealth interventions. She has identified and described novel challenges to adherence and engagement in non-urban HIV+ populations. With this knowledge and in partnership with patients and colleagues from different disciplines, she has led, since 2013, the development and implementation of the mHealth platform, PositiveLinks, which extends care beyond the clinic walls, enhances clinicians' connection with their patients, and supports people with HIV’s achievement of their health goals. This platform has been scaled to support engagement in care across Virginia, in seven other US states, in five other countries, and has been adapted for other chronic care settings such as medication assisted treatment for opioid use disorder and HPV screening.

  • E T R McQuade, Department of Epidemiology, Emory University, Atlanta, Ga, USA

    Dr. McQuade is an Associate Professor in the Department of Epidemiology, Rollins School of Public Health. Her training is in infectious disease epidemiology and her research interests are in pediatric enteric disease in low-resource settings. Specifically, she focuses on the complex interactions between early childhood diarrhea, enteric infections, environmental enteropathy, antibiotic use, and their effects on child health and development. She also studies the impact of enteric vaccines and strategies to optimize antibiotic treatment for diarrhea.

  • P O Bessong, SAMRC-University of Venda Antimicrobial Resistance and Global Health Research Unit, Thohoyandou, South Africa; Center for Global Health Equity, University of Virginia, Charlottesville, Va, USA; School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa

    Pascal Bessong is a Professor of Microbiology and Global Health at the University of Venda. His research interests include community surveillance to understand the dynamics of disease transmission and treatment outcomes, and how these interface with drug resistance development.

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Published

2025-09-02

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SAMJ Vol. 115 no. 8

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Copyright (c) 2025 M Munzhedzi, J L Guler, S Krivacsy, P Shifflett, D J Operario, R Dillingham, E T R McQuade, P O Bessong

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How to Cite

1.
Munzhedzi M, Guler JL, Krivacsy S, Shifflett P, Operario DJ, Dillingham R, et al. Prevalence of Plasmodium species in asymptomatic individuals in North-Eastern South Africa: 2018 - 2019. S Afr Med J [Internet]. 2025 Sep. 2 [cited 2026 Jan. 25];115(8):e2273. Available from: https://samajournals.co.za/index.php/samj/article/view/2273