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Frosth S, Morris ERA, Wilson H, Frykberg L, Jacobsson K, Parkhill J, Flock JI, Wood T, Guss B, Aanensen DM, Boyle AG, Riihimäki M, Cohen ND, Waller AS. Conservation of vaccine antigen sequences encoded by sequenced strains of Streptococcus equi subsp. equi. Equine Vet J 2023; 55:92-101. [PMID: 35000217 PMCID: PMC10078666 DOI: 10.1111/evj.13552] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/08/2021] [Accepted: 12/30/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Streptococcus equi subspecies equi (S equi) is the cause of Strangles, one of the most prevalent diseases of horses worldwide. Variation within the immunodominant SeM protein has been documented, but a new eight-component fusion protein vaccine, Strangvac, does not contain live S equi or SeM and conservation of the antigens it contains have not been reported. OBJECTIVE To define the diversity of the eight Strangvac antigens across a diverse S equi population. STUDY DESIGN Genomic description. METHODS Antigen sequences from the genomes of 759 S equi isolates from 19 countries, recovered between 1955 and 2018, were analysed. Predicted amino acid sequences in the antigen fragments of SEQ0256(Eq5), SEQ0402(Eq8), SEQ0721(EAG), SEQ0855(SclF), SEQ0935(CNE), SEQ0999(IdeE), SEQ1817(SclI) and SEQ2101(SclC) in Strangvac and SeM were extracted from the 759 assembled genomes and compared. RESULTS The predicted amino acid sequences of SclC, SclI and IdeE were identical across all 759 genomes. CNE was truncated in the genome of five (0.7%) isolates. SclF was absent from one genome and another encoded a single amino acid substitution. EAG was truncated in two genomes. Eq5 was truncated in four genomes and 123 genomes encoded a single amino acid substitution. Eq8 was truncated in three genomes, one genome encoded four amino acid substitutions and 398 genomes encoded a single amino acid substitution at the final amino acid of the Eq8 antigen fragment. Therefore, at least 1579 (99.9%) of 1580 amino acids in Strangvac were identical in 743 (97.9%) genomes, and all genomes encoded identical amino acid sequences for at least six of the eight Strangvac antigens. MAIN LIMITATIONS Three hundred and seven (40.4%) isolates in this study were recovered from horses in the UK. CONCLUSIONS The predicted amino acid sequences of antigens in Strangvac were highly conserved across this collection of S equi.
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Affiliation(s)
- Sara Frosth
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ellen Ruth A Morris
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, Texas, USA
| | | | - Lars Frykberg
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Karin Jacobsson
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Jan-Ingmar Flock
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Intervacc AB, Stockholm, Sweden
| | | | - Bengt Guss
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - David M Aanensen
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ashley G Boyle
- Department of Clinical Studies New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Miia Riihimäki
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Noah D Cohen
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, Texas, USA
| | - Andrew S Waller
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Intervacc AB, Stockholm, Sweden
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McGlennon A, Waller A, Verheyen K, Slater J, Grewar J, Aanensen D, Newton R. Surveillance of strangles in UK horses between 2015 and 2019 based on laboratory detection of Streptococcus equi. Vet Rec 2021; 189:e948. [PMID: 34570896 DOI: 10.1002/vetr.948] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/21/2021] [Accepted: 09/09/2021] [Indexed: 11/08/2022]
Abstract
BACKGROUND Previously national surveillance data for monitoring strangles (Streptococcus equi infection) in UK horses was limited. Improved awareness and knowledge of positive diagnoses would permit the optimisation of biosecurity protocols, decreasing the prevalence of strangles. METHODS Seven UK laboratories reported positive strangles diagnoses between 1 January 2015 and 31 December 2019 based on identifying Streptococcus equi via agent detection assays from field-based practitioner-submitted samples. Associated clinical history and animal signalment were collected where provided, and descriptive analysis undertaken. RESULTS Within the study period, 1617 laboratory-confirmed diagnoses occurred from samples submitted by 315 veterinary practices. Of these, 51.6% were swabs and 44.0% guttural pouch lavages. Diagnoses were primarily based on qPCR alone (59.6%), qPCR and culture (35.8%), or culture alone (4.6%). A total of 1791 clinical signs were reported for 713 diagnoses, where nasal discharge (31.3%) and pyrexia (20.5%) were most frequently reported. Regions with the highest number of diagnoses included North Yorkshire (n = 75, 4.6%), Staffordshire (n = 71, 4.4%) and West Sussex (North East) (n = 63, 3.9%). CONCLUSION This study presents important insights into the diagnosis and clinical features of strangles in UK horses, even though limited and/or missing clinical history and signalment on laboratory submission forms restricts the completeness of the data.
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Affiliation(s)
- Abigail McGlennon
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK.,Centre for Preventive Medicine, Animal Health Trust, Newmarket, UK
| | - Andrew Waller
- Centre for Preventive Medicine, Animal Health Trust, Newmarket, UK.,Intervacc, Hägersten, Stockholm, Sweden
| | - Kristien Verheyen
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK
| | - Josh Slater
- University of Melbourne Veterinary School, Werribee, Victoria, Australia
| | | | - David Aanensen
- Wellcome Trust Sanger Institute, Hinxton, Saffron Walden, England
| | - Richard Newton
- Centre for Preventive Medicine, Animal Health Trust, Newmarket, UK.,British Horseracing Authority, London, UK
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