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Conference papers

Globetrotting strangles: the unbridled national and international transmission of Streptococcus equi between horses

Hayley Wilson 1, 2 Catriona Mitchell 1 Karen Steward 1, 3 Amelia Charbonneau 1, 4 Saoirse Walsh 1, 5 John Timoney 6 Ulli Wernery 7 Marina Joseph 7 David Craig 8 Kees van Maanen 9 Annelies Hoogkamer-van Gennep 9 Albertine Léon 10, 11 Lucjan Witkowski 12 Magdalena Rzewuska 12 Ilona Stefańska 12 Gunther van Loon 13 Ray Cursons 14 Olivia Patty 14 Els Acke 15 James Gilkerson 16 Charles El-Hage 16 Joanne Allen 17 Hiroshi Bannai 17 yuta Kinoshita 17 Hidekazu Niwa 17 Teótimo Becú 18 John Pringle 19 Bengt Guss 19 Reinhard Böse 20 yvonne Abbott 21 Lisa Katz 21 Bernadette Leggett 21 Tom Buckley 22 Shlomo Blum 23 Fátima Cruz López 24 Ana Fernández Ros 25 Maria Cristina Marotti Campi 26 Silvia Preziuso 27 Carl Robinson 1 J. Richard Newton 1 Ellen Schofield 1, 2 Ben Brooke 1 Mike Boursnell 1 Nicolas de Brauwere 28 Roxane Kirton 28, 29 Charlotte Barton 30 Khalil Abudahab 31, 32 Ben Taylor 31, 32 Corin yeats 31, 32 Richard Goater 31, 32 David Aanensen 31, 32 Simon Harris 31, 33 Julian Parkhill 2 Matthew Holden 31, 34 Andrew Waller 1, 35, 19 
Abstract : Background: Streptococcus equi subspecies equi (S.equi) is the cause of the highly contagious equine respiratory disease ‘strangles’. Approximately 10% of recovered animals can persistently carry the bacteria and transmit it to naïve animals. The global movement of horses is an ideal mechanism for widespread transmission to geographically distant locations.Objectives: Utilise whole-genome sequence data to disentangle the transmission of S. equi and subsequent outbreaks of strangles.Study design: In vitro analysis of micro-organisms.Methods: Isolates (n = 670) of S. equi were recovered from clinical samples submitted to multiple collaborating clinics and institutions globally. Following species confirmation, isolates underwent whole-genome sequencing using Illumina technology. Sequence reads passing quality control measures were assembled and uploaded to Pathogenwatch, which assigned a phylogeny based upon sequences of core genome alleles. Population structure was inferred using the population mixture analysis in BAPS.Results: BAPS clustered the isolates into six different clusters (BAPS 1-6) and showed dominant lineages in different geographical areas but also global transmission within the clusters. Sub-groups within the clusters highlighted multiple outbreaks at local, national and international scales and highlighted population structures and transmission dynamics within single locations. For example, four different strains collected over just seven months were identified in a single location. Sequence data also identified a statistically significant decline in BAPS-5 since 2010.Main limitations: Pathogenwatch has shown its utility in investigating S. equi transmission and population structure. However, it is based upon a curated set of 1286 core genome loci. Further investigations will need to be conducted using the full spectrum of data available from whole-genome sequencing.Conclusions: Pathogenwatch was used as a tool to rapidly identify and visualise the whole-genome sequence data of a large S. equi dataset. The data demonstrate widespread transmission of multiple S. equi lineages and provide strong evidence that asymptomatic carrier horses are perpetuating this dissemination.
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Submitted on : Wednesday, October 13, 2021 - 9:15:42 AM
Last modification on : Monday, March 28, 2022 - 4:58:03 PM
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2021 - Globetrotting strangles...
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Hayley Wilson, Catriona Mitchell, Karen Steward, Amelia Charbonneau, Saoirse Walsh, et al.. Globetrotting strangles: the unbridled national and international transmission of Streptococcus equi between horses. 11th International Equine Infectious Diseases Conference, Sep 2021, Online, France. pp.20-21, ⟨10.1111/evj.17_13495⟩. ⟨hal-03375144⟩



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