Molecular genotyping and epidemiology of equine piroplasmids in South Africa.
Abstract: Recently reported substantial genetic diversity within Theileria equi 18S rRNA gene sequences has led to the identification of five genotypes A, B, C, D, and E, complicating molecular and serological diagnosis. In addition, T. haneyi has lately been reported as a species closely related to the T. equi 18S rRNA genotype C (Knowles et al., 2018). Theileria spp. of this group have a monophyletic origin and are therefore referred to as Equus group to distinguish them from the remaining Theileria lineages (Jalovecka et al., 2019). In this study, we report on the development of genotype-specific quantitative real-time PCR assays capable of detecting and distinguishing between each parasite genotype. Alignment of complete 18S rRNA sequences available on GenBank allowed for the design of a single primer pair and five TaqMan minor groove binder (MGB™) probes specific for each genotype (A-E). The assays, evaluated as qPCR simplex and two qPCR multiplex formats (Multiplex EP-ABC and Multiplex EP-DE), were shown to be both efficient and specific in the detection of T. equi genotypes. The developed qPCR assays were used to study (i) the intra-specific diversity of parasite genotypes within horse and zebra, (ii) the inter-specific differences in parasite genotype diversity in horses as compared to zebra, and (iii) the geographic distribution of T. equi 18S rRNA genotypes in South Africa. In addition, (iv) the presence of T. haneyi in South Africa was evaluated. An assessment of 342 equine field samples comprising 149 field horses, 55 racehorses, and 138 wild zebra confirmed the previously reported presence of T. equi 18S rRNA genotypes A, B, C, and D, and absence of genotype E in South African equids. Theileria equi genotypes A, B, C, and D, were detected in zebra, whereas only genotypes A, C and D, could be identified in field horses, and only genotypes A and C in racehorses. Genotypes B and D were the dominant genotypes identified in zebra in South Africa, while horses were predominantly infected with T. equi genotypes A and C. The greater diversity of T. equi genotypes in zebra suggests that it is an ancestral host for this piroplasmid lineage. Importantly, evidence is presented that each identified T. equi genotype segregates independently in each of the three studied equid populations reinforcing the notion that they represent individual separate entities corresponding to species. Preliminary investigations of the relationship between T. equi genotype C infections and Theileria haneyi, suggest that in addition to the five currently known T. equi genotypes, South African equids are also infected with T. haneyi.
Copyright © 2019 Elsevier GmbH. All rights reserved.
Publication Date: 2019-12-16 PubMed ID: 31870636DOI: 10.1016/j.ttbdis.2019.101358Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research presents a study on the genetic diversity within Theileria equi 18S rRNA gene sequences in horses and zebras in South Africa, aiding in the diagnosis of diseases spread by this parasite. This is achieved by developing genotype-specific PCR assays capable of detecting different parasite genotypes.
Study Overview
- The study utilized molecular genotyping to identify the genetic diversity within Theileria equi 18S rRNA gene sequences. Five genotypes (A, B, C, D, and E) were identified, leading to complications in molecular and serological diagnosis.
- The researchers also identified T.haneyi, a close relative to the T.equi 18S rRNA genotype C.
- The whole group of Theileria species have a common origin and are named the Equus group to distinguish them from remaining Theileria lineages.
Methodology
- A unique real-time PCR assay was designed and developed for each parasite genotype, using a single primer pair and five TaqMan minor groove binder (MGB™) probes specific to each genotype.
- The assays were evaluated in simplex and multiplex formats.
- The developed assays were used to study the intra-specific diversity of parasite genotypes within horse and zebra populations, inter-specific differences in parasite genotype diversity in horses compared to zebras, and the geographic distribution of T.equi 18S rRNA genotypes across South Africa.
Results
- Upon analysis of 342 equine field samples, T.equi 18S rRNA genotypes A, B, C, and D were identified in zebras and horses, but genotype E was absent in all South African equids.
- Most zebras had genotypes B and D, while field horses had genotypes A, C and D and race horses had only A and C.
- The greater variety of T.equi genotypes found in zebras suggests that the zebra is an ancestor host for this piroplasmid lineage.
Conclusion and Future Investigation
- The researchers concluded that each T.equi genotype found exists independently in each of the three studied equid populations, suggesting they represent separate species.
- Preliminary investigations into the relationship between T.equi genotype C infections and Theileria haneyi suggest that South African equids may also be infected with T.haneyi along with the five known T.equi genotypes.
Cite This Article
APA
Bhoora RV, Collins NE, Schnittger L, Troskie C, Marumo R, Labuschagne K, Smith RM, Dalton DL, Mbizeni S.
(2019).
Molecular genotyping and epidemiology of equine piroplasmids in South Africa.
Ticks Tick Borne Dis, 11(2), 101358.
https://doi.org/10.1016/j.ttbdis.2019.101358 Publication
Researcher Affiliations
- Epidemiology, Parasites and Vectors, Agricultural Research Council, Onderstepoort Veterinary Research, Onderstepoort, 0110, South Africa; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa. Electronic address: BhooraR@arc.agric.za.
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
- Instituto de Patobiologia Veterinaria, Centre of Research in Veterinary and Agronomic Sciences, INTA-Castelar, Prov. De Buenos Aires, Argentina; National Research Council of Argentina (CONICET), Av. Rivadavia 1917, C1033AAJ, CABA, Argentina.
- Epidemiology, Parasites and Vectors, Agricultural Research Council, Onderstepoort Veterinary Research, Onderstepoort, 0110, South Africa.
- Epidemiology, Parasites and Vectors, Agricultural Research Council, Onderstepoort Veterinary Research, Onderstepoort, 0110, South Africa.
- Epidemiology, Parasites and Vectors, Agricultural Research Council, Onderstepoort Veterinary Research, Onderstepoort, 0110, South Africa.
- South African National Biodiversity Institute (SANBI), National Zoological Garden, Pretoria, South Africa.
- South African National Biodiversity Institute (SANBI), National Zoological Garden, Pretoria, South Africa; Department of Zoology, University of Venda, Thohoyandou, South Africa.
- Epidemiology, Parasites and Vectors, Agricultural Research Council, Onderstepoort Veterinary Research, Onderstepoort, 0110, South Africa; Department of Agriculture and Animal Health, University of South Africa, South Africa.
MeSH Terms
- Animals
- Base Sequence
- Equidae
- Genotype
- Horse Diseases / epidemiology
- Horse Diseases / parasitology
- Horses
- RNA, Protozoan / analysis
- RNA, Ribosomal, 18S / analysis
- Sequence Alignment / veterinary
- South Africa / epidemiology
- Theileria / genetics
- Theileriasis / epidemiology
- Theileriasis / parasitology
Citations
This article has been cited 15 times.- Haynes E, Lorch J, Allender MC. Development and application of a qPCR-based genotyping assay for Ophidiomyces ophidiicola to investigate the epidemiology of ophidiomycosis.. PLoS One 2023;18(8):e0289159.
- Ravindran R, Hembram PK, Kumar GS, Kumar KGA, Deepa CK, Varghese A. Transovarial transmission of pathogenic protozoa and rickettsial organisms in ticks.. Parasitol Res 2023 Mar;122(3):691-704.
- Mongruel ACB, Medici EP, da Costa Canena A, Calchi AC, Perles L, Rodrigues BCB, Soares JF, Machado RZ, André MR. Theileria terrestris nov. sp.: A Novel Theileria in Lowland Tapirs (Tapirus terrestris) from Two Different Biomes in Brazil.. Microorganisms 2022 Nov 23;10(12).
- Coultous R, Gotić J, McCann M, Sutton D, Beck R, Shiels B. Novel equi merozoite antigen (ema-1) gene heterogeneity in a geographically isolated Theileria equi population in Croatia.. Parasit Vectors 2022 Oct 31;15(1):401.
- Iweriebor BC, Afolabi KO, Nqoro A, Obi LC. Emergence of Theileria species in ticks from free-ranging domestic animals in Raymond Mhlaba local municipality, South Africa.. Heliyon 2022 Mar;8(3):e09085.
- Sears KP, Knowles DP, Fry LM. Clinical Progression of Theileria haneyi in Splenectomized Horses Reveals Decreased Virulence Compared to Theileria equi.. Pathogens 2022 Feb 16;11(2).
- Schnittger L, Ganzinelli S, Bhoora R, Omondi D, Nijhof AM, Florin-Christensen M. The Piroplasmida Babesia, Cytauxzoon, and Theileria in farm and companion animals: species compilation, molecular phylogeny, and evolutionary insights.. Parasitol Res 2022 May;121(5):1207-1245.
- Elsawy BSM, Nassar AM, Alzan HF, Bhoora RV, Ozubek S, Mahmoud MS, Kandil OM, Mahdy OA. Rapid Detection of Equine Piroplasms Using Multiplex PCR and First Genetic Characterization of Theileria haneyi in Egypt.. Pathogens 2021 Oct 31;10(11).
- Bastos RG, Sears KP, Dinkel KD, Kappmeyer L, Ueti MW, Knowles DP, Fry LM. Development of an Indirect ELISA to Detect Equine Antibodies to Theileria haneyi.. Pathogens 2021 Feb 27;10(3).
- Adelabu OA, Iweriebor BC, Okoh AI, Obi LC. Genomic Profiling for Piroplasms in Feeding Ixodid Ticks in the Eastern Cape, South Africa.. Pathogens 2020 Dec 18;9(12).
- Sears K, Knowles D, Dinkel K, Mshelia PW, Onzere C, Silva M, Fry L. Imidocarb Dipropionate Lacks Efficacy against Theileria haneyi and Fails to Consistently Clear Theileria equi in Horses Co-Infected with T. haneyi.. Pathogens 2020 Dec 10;9(12).
- Tirosh-Levy S, Gottlieb Y, Fry LM, Knowles DP, Steinman A. Twenty Years of Equine Piroplasmosis Research: Global Distribution, Molecular Diagnosis, and Phylogeny.. Pathogens 2020 Nov 8;9(11).
- Mshelia PW, Kappmeyer L, Johnson WC, Kudi CA, Oluyinka OO, Balogun EO, Richard EE, Onoja E, Sears KP, Ueti MW. Molecular detection of Theileria species and Babesia caballi from horses in Nigeria.. Parasitol Res 2020 Sep;119(9):2955-2963.
- Onyiche TE, Taioe MO, Ogo NI, Sivakumar T, Biu AA, Mbaya AW, Xuan X, Yokoyama N, Thekisoe O. Molecular evidence of Babesia caballi and Theileria equi in equines and ticks in Nigeria: prevalence and risk factors analysis.. Parasitology 2020 Sep;147(11):1238-1248.
- Bishop RP, Kappmeyer LS, Onzere CK, Odongo DO, Githaka N, Sears KP, Knowles DP, Fry LM. Equid infective Theileria cluster in distinct 18S rRNA gene clades comprising multiple taxa with unusually broad mammalian host ranges.. Parasit Vectors 2020 May 19;13(1):261.
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