Quantitative detection of Theileria haneyi in South African horses.
Abstract: Theileria haneyi is an apicomplexan parasite closely related to Theileria equi, a known causative agent of equine piroplasmosis. The molecular distinction between these parasites relies on a nested polymerase chain reaction (PCR) assay, which has been reported to be unreliable. A recently reported indirect ELISA based on equi merozoite antigen 11 (Thema-11) of T. haneyi can detect geographically diverse T. haneyi strains. Since the ema-11 gene is exclusive to T. haneyi, it was chosen as the target for developing a TaqMan minor groove binder (MGB™) quantitative real-time PCR (qPCR). Published T. haneyi ema-11 gene sequences were used to design primers to amplify the ema-11 gene, and ema-11 amplicons from South African samples were cloned and sequenced. An alignment of the South African ema-11 gene sequences with published T. haneyi ema-11 gene sequences enabled the identification of a conserved region for the design of the qPCR assay. The T. haneyi ema-11 (Thema-11) qPCR assay was efficient, specific, and sensitive in detecting T. haneyi ema-11. The detection limit was determined to be 1.169 × 10 % parasitized erythrocytes. The performance of the Thema-11 qPCR assay was evaluated together with a T. equi ema-1-specific qPCR assay. Theileria haneyi was detected in 67.6 % of the South African field samples screened, while the occurrence of T. equi based on the quantitative amplification of the ema-1 gene was higher (91.8 %). Our results suggest that combined, the Thema-11 and T. equi ema-1 qPCR assays could detect and differentiate between T. haneyi and T. equi infections.
Copyright © 2025 The Authors. Published by Elsevier GmbH.. All rights reserved.
Publication Date: 2025-05-11 PubMed ID: 40354693DOI: 10.1016/j.ttbdis.2025.102487Google Scholar: Lookup
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Summary
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The research article focuses on the development of a new method to detect Theileria haneyi, a parasite that affects horses, in South Africa. Using the ema-11 gene that is exclusive to T. haneyi, researchers developed a quantitative real-time PCR (qPCR) assay for efficient, accurate detection of the parasite.
Background of Research
- Theileria Haneyi is an apicomplexan parasite closely related to Theileria Equi, a known causative agent of equine piroplasmosis, a severe disease in horses. Traditionally, these parasites’ distinction depends on a nested polymerase chain reaction (PCR) assay, which has proven unreliable.
- Recent research has revealed that an indirect ELISA based on equi merozoite antigen 11 (Thema-11) of T. haneyi is capable of detecting diverse strains of the parasite, providing a way forward.
Methodology
- Since the ema-11 gene is exclusive to T. haneyi, it was selected as the target for developing a quantitative real-time PCR (qPCR) assay.
- The researchers designed primers to amplify the ema-11 gene using published T. haneyi ema-11 gene sequences, and amped these from South African samples which they then cloned and sequenced.
- The alignment of the South African ema-11 gene sequences with published T. haneyi ema-11 gene sequences from other sources helped the researchers identify a conserved region suitable for designing the qPCR assay.
Results and Conclusion
- The developed qPCR assay, known as the Theileria haneyi ema-11 (Thema-11), proved efficient, specific, and sensitive in detecting the T. haneyi ema-11.
- It was found that the detection limit of the Thema-11 qPCR assay was 1.169 × 10 % of parasitized erythrocytes – the red blood cells in which the parasite resides.
- The Thema-11 qPCR assay’s performance was evaluated alongside a T. equi ema-1-specific qPCR assay, another qPCR assay designed to detect a different strain of the parasite.
- In South African field samples screened, Theileria haneyi was detected in 67.6% of the cases, while T. equi was detected more frequently (in 91.8% of the cases).
- These findings suggest that a combined approach using both the Thema-11 and T. equi ema-1 qPCR assays could detect and differentiate between T. haneyi and T. equi infections effectively.
Cite This Article
APA
Bhoora RV, Mbaba TV, Troskie M, Ackermann RE, Collins NE.
(2025).
Quantitative detection of Theileria haneyi in South African horses.
Ticks Tick Borne Dis, 16(3), 102487.
https://doi.org/10.1016/j.ttbdis.2025.102487 Publication
Researcher Affiliations
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa. Electronic address: raksha.vasantraibhoora@up.ac.za.
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
Conflict of Interest Statement
Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Citations
This article has been cited 1 times.- Hacilarlioglu S, Bilgic HB, Karagenc T, Aydin HB, Toker H, Kanlioglu H, Pekagirbas M, Bakirci S. Molecular Detection and Prevalence of Equine Piroplasmosis and Other Blood Parasites in Equids of Western Aegean Türkiye. Vet Sci 2025 Aug 27;12(9).