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Li L, Li S, Ma H, Akhtar MF, Tan Y, Wang T, Liu W, Khan A, Khan MZ, Wang C. An Overview of Infectious and Non-Infectious Causes of Pregnancy Losses in Equine. Animals (Basel) 2024; 14:1961. [PMID: 38998073 PMCID: PMC11240482 DOI: 10.3390/ani14131961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 06/25/2024] [Accepted: 06/28/2024] [Indexed: 07/14/2024] Open
Abstract
Equine breeding plays an essential role in the local economic development of many countries, and it has experienced rapid growth in China in recent years. However, the equine industry, particularly large-scale donkey farms, faces a significant challenge with pregnancy losses. Unfortunately, there is a lack of systematic research on abortion during equine breeding. Several causes, both infectious and non-infectious, of pregnancy losses have been documented in equines. The infectious causes are viruses, bacteria, parasites, and fungi. Non-infectious causes may include long transportation, ingestion of mycotoxins, hormonal disturbances, twinning, placentitis, umbilical length and torsion, etc. In current review, we discuss the transmission routes, diagnostic methods, and control measures for these infectious agents. Early detection of the cause and appropriate management are crucial in preventing pregnancy loss in equine practice. This review aims to provide a comprehensive understanding of the potential causes of abortion in equines, including infectious agents and non-infectious factors. It emphasizes the importance of continued research and effective control measures to address this significant challenge in the equine industry.
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Affiliation(s)
- Liangliang Li
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
| | - Shuwen Li
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
| | - Haoran Ma
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
| | - Muhammad Faheem Akhtar
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
| | - Ying Tan
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
| | - Tongtong Wang
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
| | - Wenhua Liu
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao 266109, China
| | - Adnan Khan
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 511464, China
| | - Muhammad Zahoor Khan
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
| | - Changfa Wang
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China; (L.L.)
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Cui Y, Cao M, Yu F, Zhao A, Tao D, Zhu T, Zhang Z, Qi M. Molecular detection of piroplasms in domestic donkeys in Xinjiang, China. Vet Med Sci 2024; 10:e1468. [PMID: 38879882 PMCID: PMC11180456 DOI: 10.1002/vms3.1468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/09/2024] [Accepted: 04/21/2024] [Indexed: 06/18/2024] Open
Abstract
BACKGROUND Piroplasmosis is a common and prevalent tick-borne disease that affects equids. OBJECTIVES To determine the infection and molecular characteristics of the piroplasms in donkeys from Xinjiang, northwestern China, we undertook a cross sectional study by collecting representative samples across several counties within the region. METHODS A total of 344 blood samples were collected from adult domestic donkeys from 13 counties in Xinjiang. PCR was conducted to test for T. equi and B. caballi in the blood samples based on the equine merozoite antigen-1 (Ema-1) gene and the 48 kDa rhoptry protein (BC48) gene, respectively. RESULTS Sixteen blood samples tested positive for piroplasms and the overall infection rate was 4.7% (16/344). Seven of the 13 counties were positive for piroplasms. Among the 16 piroplasm-positive samples, 15 were singly infected with T. equi with an infection rate of 4.4% (15/344), and coinfection with T. equi and B. caballi was detected in one sample (0.3%, 1/344) from Wushi. Four T. equi sequence genotypes were identified and grouped into different branches of the evolutionary trees. CONCLUSION These findings suggest that the infection rate of piroplasms is low in domestic donkeys in southern Xinjiang and that T. equi genotypes have a regional distribution.
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Affiliation(s)
- Yanyan Cui
- School of Biotechnology and Food, Shangqiu Normal University, Shangqiu, PR China
| | - Mengya Cao
- College of Animal Science and Technology, Tarim University, Alar, Xinjiang, PR China
| | - Fuchang Yu
- College of Animal Science and Technology, Tarim University, Alar, Xinjiang, PR China
| | - Aiyun Zhao
- College of Animal Science and Technology, Tarim University, Alar, Xinjiang, PR China
| | - Dayong Tao
- College of Animal Science and Technology, Tarim University, Alar, Xinjiang, PR China
| | - Tingting Zhu
- College of Animal Science and Technology, Tarim University, Alar, Xinjiang, PR China
| | - Zhenjie Zhang
- College of Animal Science and Technology, Tarim University, Alar, Xinjiang, PR China
| | - Meng Qi
- College of Animal Science and Technology, Tarim University, Alar, Xinjiang, PR China
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Nehra AK, Kumari A, Moudgil AD, Vohra S. Revisiting the genotypes of Theileria equi based on the V4 hypervariable region of the 18S rRNA gene. Front Vet Sci 2024; 11:1303090. [PMID: 38560630 PMCID: PMC10978764 DOI: 10.3389/fvets.2024.1303090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 02/27/2024] [Indexed: 04/04/2024] Open
Abstract
Introduction Equine theileriosis, an economically important disease that affects horses and other equids worldwide, is caused by a tick-borne intracellular apicomplexan protozoa Theileria equi. Genotyping of T. equi based on the 18S rRNA gene revealed the presence of two, three, four or five genotypes. In previous published reports, these genotypes have been labelled either alphabetically or numerically, and there is no uniformity in naming of these genotypes. The present study was aimed to revisit the phylogeny, genetic diversity and geographical distribution of T. equi based on the nucleotide sequences of the V4 hypervariable region of the 18S rRNA gene available in the nucleotide databases. Methods Out of 14792 nucleotide sequences of T. equi available in the GenBank™, only 736 sequences of T. equi containing the complete V4 hypervariable region of the 18S rRNA gene (>207 bp) were used in multiple sequence alignment. Subsequently, a maximum likelihood phylogenetic tree was constructed based on the Kimura 2-parameter model (K2+I). Results The phylogenetic tree placed all the sequences into four distinct clades with high bootstrap values which were designated as T. equi clades/ genotypes A, B, C and D. Our results indicated that the genotype B of Nagore et al. and genotype E of Qablan et al. together formed the clade B with a high bootstrap value (95%). Furthermore, all the genotypes probably originated from clade B, which was the most dominant genotype (52.85%) followed by clades A (27.58%), and C (9.78%) and D (9.78%). Genotype C manifested a comparatively higher genetic diversity (91.0-100% identity) followed by genotypes A (93.2-99.5%), and B and D (95.7-100%). The alignment report of the consensus nucleotide sequences of the V4 hypervariable region of the 18S rRNA gene of four T. equi genotypes (A-D) revealed significant variations in one region, between nucleotide positions 113-183, and 41 molecular signatures were recognized. As far as geographical distribution is concerned, genotypes A and C exhibited far-extending geographical distribution involving 31 and 13 countries of the Asian, African, European, North American and South American continents, respectively. On the contrary, the genotypes B and D exemplified limited distribution with confinement to 21 and 12 countries of Asian, African and European continents, respectively. Interestingly, genotypes A and C have been reported from only two continents, viz., North and South America. It was observed that genotypes A and C, and B and D exhibit similar geographical distribution. Discussion The present study indicated the presence of only four previously described T. equi genotypes (A, B, C and D) after performing the molecular analyses of all available sequences of the complete V4 hypervariable region of the 18S rRNA gene of T. equi isolates in the GenBank™.
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Affiliation(s)
- Anil Kumar Nehra
- Department of Veterinary Parasitology, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India
| | - Ansu Kumari
- Department of Veterinary Medicine, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India
| | - Aman Dev Moudgil
- Department of Veterinary Parasitology, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India
| | - Sukhdeep Vohra
- Department of Veterinary Parasitology, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India
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Kamran K, Akbar A, Naseem M, Samad A, Samiullah, Achakzai JK, Rehman ZU, Sohail Sajid M, Ali A. Participatory appraisal for healthcare and welfare management strategies of donkeys (Equus ascinus) in Balochistan, Pakistan. Front Vet Sci 2022; 9:1005079. [PMID: 36118345 PMCID: PMC9478909 DOI: 10.3389/fvets.2022.1005079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/15/2022] [Indexed: 11/26/2022] Open
Abstract
In spite of the significant importance of the donkeys (Equus ascinus) as draft animal in resource-poor countries like Pakistan, they are equines not receiving the appropriate care. They face challenges including injuries, diseases, lack of basic environment and mismanagement by their owners. The present study aims to provide a brief update on the current status of management of healthcare and the welfare of domestic donkeys using participatory epidemiological tools. These tools can help to provide better strategies for improving their productivity and inclusion in human society. This study was mainly focused only on donkeys and horses, mules and ponies were excluded from the study. We carried out a systematic review of the relevant available published literature and shortlisted 50 articles reporting on the different health related characteristics of donkeys. A comprehensive questionnaire was completed by 191 donkey owners, including nine farriers (all men, average age = 38.24 ± 12.43) over a time span from October 2021 to March 2022. Multivariate Odds Ratios (MORs) and 95% confidence intervals were used to assess the predictions of health management and welfare measures for the surveyed donkeys. The most common observed medical problems in donkey health were hyperlipaemia (28.06%), lameness (16.33%) and dental (20.41%) problems. One-third (34.31%) of the donkeys were underweight. The dull donkey with poor appetite needs a clinical emergency owing to a high risk of developing hyperlipemia, which may be life-threatening. These findings are quite useful for the improvement of healthcare management and the welfare of donkeys.
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Seroprevalence of Anti- Theileria equi Antibodies in Horses from Three Geographically Distinct Areas of Romania. Pathogens 2022; 11:pathogens11060669. [PMID: 35745523 PMCID: PMC9229635 DOI: 10.3390/pathogens11060669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/05/2022] [Accepted: 06/08/2022] [Indexed: 02/01/2023] Open
Abstract
Equine piroplasmosis (EP) is an endemic tick-borne disease found in most countries around the world. It affects all species of Equidae, and it is caused by Theileria equi, Babesia caballi and T. haneyi. The research herein is the second study on the prevalence of piroplasms in Romania conducted in the past two decades. The aim of this study was to assess the seroprevalence of anti-Theileria equi antibodies and the geographical distribution of this disease in the southwest, west, and northwest regions of Romania in order to obtain a more thorough understanding of the parasitological status of horses in this country. This study included 522 apparently healthy, mixed-breed horses from three different counties. The serum samples were analysed using the cELISA Theileria equi Antibody Test Kit. The overall seroprevalence rate was 12.84%. From the total number of positive horses, 13.96% were females and 11.21% were males. Based on the distribution of positive cases into age groups, the following values were obtained: 0−60 months: 16.26%, 60−180 months: 10.03%, and >180 months: 15.83%. There was no statistically significant difference between samples, based on age or gender. The positivity percentage in the localities included in the study ranged from 8.33 to 100%. In the population under study, the seroprevalence rate was high, indicating a possible exposure risk in this area of Romania, which could have severe effects on equids in the case of clinical manifestations of the disease. EP represents a serious threat for equine health in Romania; therefore, close and continuous monitoring of the situation is required.
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Ahedor B, Kothalawala H, Kanagaratnam R, Vimalakumar SC, Otgonsuren D, Tuvshintulga B, Batmagnai E, Silva SSP, Sivakumar T, Yokoyama N. First detection of Theileria equi in free-roaming donkeys (Equus africanus asinus) in Sri Lanka. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 99:105244. [PMID: 35149223 DOI: 10.1016/j.meegid.2022.105244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 01/13/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Equine piroplasmosis (EP) is a tick-borne disease caused by Theileria equi and Babesia caballi in equids, including horses, donkeys, zebras, and mules. It is globally endemic with significant economic impact on the equine industry. Infected animals may serve as carriers, and they may be a source of infection for ticks, thereby posing a great challenge for disease management. Sri Lanka is a tropical country, where infections by various tick-borne parasites are common among livestock animals. However, infections by T. equi and B. caballi remain unstudied in Sri Lanka. Therefore, in the present study, we conducted an epidemiological survey to investigate the presence of T. equi and B. caballi in apparently healthy free-roaming donkeys. Blood samples were randomly taken from 111 donkeys in Mannar (n = 100) and Kilinochchi (n = 11) districts in Sri Lanka. Thin blood smears were prepared from the blood samples and subjected to microscopic examination. Additionally, blood DNA samples were prepared and screened for T. equi and B. caballi infections using species-specific PCR assays. Our results showed that 64 (57.7%) and 95 (85.6%) of the donkeys were positive for T. equi by microscopy and PCR, respectively. However, all samples were negative for B. caballi. Phylogenetic analysis of the T. equi 18S rRNA sequences detected two distinct genotypes, namely C and D. To our knowledge, this is the first report of T. equi in Sri Lanka and of genotype C in donkeys. The present study highlights the importance of monitoring the shrinking donkey population in Sri Lanka owing to EP caused by T. equi.
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Affiliation(s)
- Believe Ahedor
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan; Department of Animal Experimentation, Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | | | | | | | - Davaajav Otgonsuren
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Bumduuren Tuvshintulga
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Enkhbaatar Batmagnai
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | | | - Thillaiampalam Sivakumar
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan; OIE Reference Laboratory for Equine Piroplasmosis, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan.
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Ji N, Chen X, Liu G, Zhao S, Tan W, Liu G, Zhang J, Wang Y. Theileria, Hepatozoon and Taenia infection in great gerbils ( Rhombomys opimus) in northwestern China. Int J Parasitol Parasites Wildl 2021; 15:79-86. [PMID: 33996439 PMCID: PMC8099453 DOI: 10.1016/j.ijppaw.2021.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 04/05/2021] [Accepted: 04/05/2021] [Indexed: 11/25/2022]
Abstract
The great gerbil (Rhombomys opimus), widely distributed in Asia, is a natural reservoir for Yersinia pestis, Leishmania donovani and some species of helminths. In this study, 188 great gerbils were sampled in Alataw City and Manas County, northwestern China, and tested for the presence of Theileria, Hepatozoon and Taenia species by molecular methods. Theileria sp., named as "Candidatus Theileria xinjiangensis", was detected in heart, liver, spleen, lung, and kidney of 6.9% rodents. Six genotypes of "Taenia sp. Rhombomys opimus", which were close to Taenia laticollis (87.3-94.0% identities), were detected in cyst liquid of 5.3% rodents. "Hepatozoon ayorgbor-like" haemogregarines was detected in spleens of 1.6% rodents. To our best knowledge, Candidatus Theileria xinjiangensis, Hepatozoon ayorgbor-like and genotypes of "Taenia sp. Rhombomys opimus" were found for the first time in the great gerbil. These results extend our knowledge on the diversity and pathogenesis of Theileria, Hepatozoon and Taenia species.
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Affiliation(s)
- Na Ji
- Department of Basic Medicine, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region 832002, People's Republic of China
| | - Xueling Chen
- Department of Basic Medicine, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region 832002, People's Republic of China
| | - Gang Liu
- Department of Basic Medicine, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region 832002, People's Republic of China
| | - Shanshan Zhao
- Department of Basic Medicine, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region 832002, People's Republic of China
| | - Wenbo Tan
- Department of Basic Medicine, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region 832002, People's Republic of China
| | - Guangyuan Liu
- Lanzhou Veterinary Research Institute, Lanzhou, China
| | - Jiangguo Zhang
- Alataw Customs, Alashankou, Xinjiang Uygur Autonomous Region 833418, China
| | - Yuanzhi Wang
- Department of Basic Medicine, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region 832002, People's Republic of China
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Tirosh-Levy S, Mazuz ML, Savitsky I, Pinkas D, Gottlieb Y, Steinman A. Serological and Molecular Prevalence of Babesia caballi in Apparently Healthy Horses in Israel. Pathogens 2021; 10:pathogens10040445. [PMID: 33917822 PMCID: PMC8068206 DOI: 10.3390/pathogens10040445] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/26/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
Babesia caballi is a tick-borne hemoparasite of equines and one of the causative agents of equine piroplasmosis, which poses a great concern for the equine industry regarding animal welfare and international horse movement. The parasite is endemic in Israel; however, its seroprevalence in the area was never evaluated due to antigenic heterogenicity in the gene used in the commercially available kit. Blood samples were collected from 257 horses at 19 farms throughout the country and screened for the presence of anti-B. caballi antibodies via an indirect immunofluorescent antibody test (IFAT) and for the presence of parasite DNA by nested PCR. The seroprevalence of B. caballi was 69.6% and its molecular prevalence was 9.7%. The geographical area, horse’s sex, breed, housing, exposure to ticks, and specifically to Hyalomma marginatum, and co-infection with Theileria equi were found to be significantly associated with serologic exposure in univariable analysis, while the geographical area and horses’ sex remained significant in the multivariable analysis. The results of this study demonstrate a high level of exposure to B. caballi and identify important risk factors for infection. The difference between the serological and molecular prevalence, probably related to parasite clearance, is also highlighted.
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Affiliation(s)
- Sharon Tirosh-Levy
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (D.P.); (Y.G.); (A.S.)
- Division of Parasitology, Kimron Veterinary Institute, Beit Dagan 50250, Israel; (M.L.M.); (I.S.)
- Correspondence:
| | - Monica L. Mazuz
- Division of Parasitology, Kimron Veterinary Institute, Beit Dagan 50250, Israel; (M.L.M.); (I.S.)
| | - Igor Savitsky
- Division of Parasitology, Kimron Veterinary Institute, Beit Dagan 50250, Israel; (M.L.M.); (I.S.)
| | - Dana Pinkas
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (D.P.); (Y.G.); (A.S.)
| | - Yuval Gottlieb
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (D.P.); (Y.G.); (A.S.)
| | - Amir Steinman
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (D.P.); (Y.G.); (A.S.)
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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; 9:E926. [PMID: 33171698 PMCID: PMC7695325 DOI: 10.3390/pathogens9110926] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/04/2020] [Accepted: 11/04/2020] [Indexed: 12/26/2022] Open
Abstract
Equine piroplasmosis (EP), caused by the hemoparasites Theileria equi, Theileria haneyi, and Babesia caballi, is an important tick-borne disease of equines that is prevalent in most parts of the world. Infection may affect animal welfare and has economic impacts related to limitations in horse transport between endemic and non-endemic regions, reduced performance of sport horses and treatment costs. Here, we analyzed the epidemiological, serological, and molecular diagnostic data published in the last 20 years, and all DNA sequences submitted to GenBank database, to describe the current global prevalence of these parasites. We demonstrate that EP is endemic in most parts of the world, and that it is spreading into more temperate climates. We emphasize the importance of using DNA sequencing and genotyping to monitor the spread of parasites, and point to the necessity of further studies to improve genotypic characterization of newly recognized parasite species and strains, and their linkage to virulence.
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Affiliation(s)
- Sharon Tirosh-Levy
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (Y.G.); (A.S.)
| | - Yuval Gottlieb
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (Y.G.); (A.S.)
| | - Lindsay M. Fry
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (L.M.F.); (D.P.K.)
- Animal Disease Research Unit, Agricultural Research Service, US Department of Agriculture, Pullman, WA 99164, USA
| | - Donald P. Knowles
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (L.M.F.); (D.P.K.)
| | - Amir Steinman
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (Y.G.); (A.S.)
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Tirosh-Levy S, Steinman A, Levy H, Katz Y, Shtilman M, Gottlieb Y. Parasite load and genotype are associated with clinical outcome of piroplasm-infected equines in Israel. Parasit Vectors 2020; 13:267. [PMID: 32434550 PMCID: PMC7240905 DOI: 10.1186/s13071-020-04133-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 05/11/2020] [Indexed: 02/08/2023] Open
Abstract
Background Equine piroplasmosis is a highly endemic protozoan disease of horses worldwide, caused by Theileria equi and Babesia caballi. While most horses in endemic areas are subclinically infected, the mechanisms leading to clinical outcome are vastly unknown. Moreover, since clinical signs of disease are not specific, and the prevalence in endemic areas is high, it is difficult to determine if equine piroplasmosis is the cause of disease. To identify possible mechanisms leading to the clinical outcome in an endemic area, we compared parasite loads and genotypes in clinically and subclinically infected horses. Methods Blood was collected from horses with clinical signs consistent with equine piroplasmosis, and from apparently healthy horses in Israel. Packed cell volume and total solids were measured. Quantitative and diagnostic polymerase chain reaction were used to identify, quantify and classify equine piroplasmosis infection. Phylogenetic analyses were used to determine the genotype of both parasites. Results For both parasites, clinical cases were associated with low mean packed cell volume and high mean parasite load (P < 0.001), enabling the determination of a cut-off value to distinguish between clinically and subclinically infected horses. Samples of Theileria equi from subclinical horses were classified into three different 18S rRNA genotypes, D (n = 23), A (n = 12) and C (n = 5), while samples from all clinical cases (n = 6) were classified as genotype A. The sequences of T. equi equi merozoite antigens 1 (ema-1, n = 9) and 2 (ema-2, n = 11) genes were fairly conserved and did not differ between clinical and subclinical cases. Babesia caballi rhoptry associated protein-1 (rap-1) was classified into sub-genotypes A1 (n = 14) and A2 (n = 5) with no association to clinical outcome. Classification of the 18S rRNA gene (sub-genotypes B1 and B2) agreed with the rap-1 classification. Conclusions The results of this study suggest that quantification of parasite loads of infected horses may be used to distinguish between infections resulting in disease and subclinical cases. Although number of clinical cases is limited, we identified T. equi 18S rRNA genotype A to be associated with clinical disease. This finding emphasizes the importance of in-depth genetic characterization of T. equi genotypes to identify possible markers for virulence.![]()
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Affiliation(s)
- Sharon Tirosh-Levy
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Amir Steinman
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Hadas Levy
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yotam Katz
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Margarita Shtilman
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yuval Gottlieb
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
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