{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T01:43:17Z","timestamp":1789609397668,"version":"build-2803163510"},"reference-count":25,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2023,1,20]],"date-time":"2023-01-20T00:00:00Z","timestamp":1674172800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Merck Animal Health"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>This study aimed to describe selected epidemiological aspects of horses with acute onset of fever and respiratory signs testing qPCR-positive for S. equi and to determine the effect of vaccination against S. equi on qPCR status. Horses with acute onset of fever and respiratory signs from all regions of the United States were included in a voluntary biosurveillance program from 2008 to 2020 and nasal secretions were tested via qPCR for S. equi and common respiratory viruses. A total of 715\/9409 equids (7.6%) tested qPCR-positive for S. equi, with 226 horses showing coinfections with EIV, EHV-1, EHV-4, and ERBV. The median age for the S. equi qPCR-positive horses was 8 \u00b1 4 years and there was significant difference when compared to the median age of the S. equi qPCR-negative horses (6 \u00b1 2 years; p = 0.004). Quarter Horse, Warmblood, and Thoroughbred were the more frequent breed in this horse population, and these breeds were more likely to test qPCR-positive for S. equi compared to other breeds. There was not statistical difference for sex between S. equi qPCR-positive and qPCR-negative horses. Horses used for competition and ranch\/farm use were more likely to test qPCR-positive for S. equi (p = 0.006). Horses that tested S. equi qPCR-positive were more likely to display nasal discharge, fever, lethargy, anorexia, and ocular discharge compared to horses that tested S. equi qPCR-negative (p = 0.001). Vaccination against S. equi was associated with a lower frequency of S. equi qPCR-positive status.<\/jats:p>","DOI":"10.3390\/vetsci10020078","type":"journal-article","created":{"date-parts":[[2023,1,20]],"date-time":"2023-01-20T02:52:21Z","timestamp":1674183141000},"page":"78","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Voluntary Biosurveillance of Streptococcus equi Subsp. equi in Nasal Secretions of 9409 Equids with Upper Airway Infection in the USA"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6227-8572","authenticated-orcid":false,"given":"Camilo","family":"Jaramillo-Morales","sequence":"first","affiliation":[{"name":"William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kaitlyn","family":"James","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, Gynecology and Reproduction Biology, Massachusetts General Hospital, Boston, MA 02114, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samantha","family":"Barnum","sequence":"additional","affiliation":[{"name":"Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wendy","family":"Vaala","sequence":"additional","affiliation":[{"name":"Merck Animal Health, Madison, NJ 07940, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9978-5546","authenticated-orcid":false,"given":"Duane E.","family":"Chappell","sequence":"additional","affiliation":[{"name":"Merck Animal Health, Madison, NJ 07940, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7462-4532","authenticated-orcid":false,"given":"Chrissie","family":"Schneider","sequence":"additional","affiliation":[{"name":"Merck Animal Health, Madison, NJ 07940, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bryant","family":"Craig","sequence":"additional","affiliation":[{"name":"Merck Animal Health, Madison, NJ 07940, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fairfield","family":"Bain","sequence":"additional","affiliation":[{"name":"Merck Animal Health, Madison, NJ 07940, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D. Craig","family":"Barnett","sequence":"additional","affiliation":[{"name":"Merck Animal Health, Madison, NJ 07940, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Earl","family":"Gaughan","sequence":"additional","affiliation":[{"name":"Merck Animal Health, Madison, NJ 07940, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicola","family":"Pusterla","sequence":"additional","affiliation":[{"name":"Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1111\/evj.12659","article-title":"Strangles: A modern clinical view from the 17th century","volume":"49","author":"Paillot","year":"2017","journal-title":"Equine Vet. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1136\/vr.i123","article-title":"Strangles: A pathogenic legacy of the war horse","volume":"178","author":"Waller","year":"2016","journal-title":"Vet. Rec."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1136\/vr.d2157","article-title":"Surveillance programme for important equine infectious respiratory pathogens in the USA","volume":"169","author":"Pusterla","year":"2011","journal-title":"Vet. Rec."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1111\/j.1939-1676.2005.tb02671.x","article-title":"Streptococcus equi infections in horses: Guidelines for treatment, control, and prevention of strangles","volume":"19","author":"Sweeney","year":"2005","journal-title":"J. Vet. Intern. Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1111\/jvim.15043","article-title":"Streptococcus equi infections in horses: Guidelines for treatment, control, and prevention of strangles\u2014Revised consensus statement","volume":"32","author":"Boyle","year":"2018","journal-title":"J. Vet. Intern. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"108638","DOI":"10.1016\/j.vetmic.2020.108638","article-title":"Comparison of whole genome sequences of Streptococcus equi subsp equi from an outbreak in Texas with isolates from within the region, Kentucky, USA, and other countries","volume":"243","author":"Morris","year":"2020","journal-title":"Vet. Microbiol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"284","DOI":"10.2746\/042516407X195961","article-title":"Modified live Streptococcus equi (\u2018strangles\u2019) vaccination followed by clinically adverse reactions associated with bacterial replication","volume":"39","author":"Kemble","year":"2007","journal-title":"Equine Vet. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e948","DOI":"10.1002\/vetr.948","article-title":"Surveillance of strangles in UK horses between 2015 and 2019 based on laboratory detection of Streptococcus equi","volume":"189","author":"McGlennon","year":"2021","journal-title":"Vet. Rec."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/j.rvsc.2015.11.009","article-title":"Prevalence of Streptococcus equi subsp equi in horses and associated risk factors in the State of Rio Grande do Sul, Brazil","volume":"104","author":"Libardoni","year":"2016","journal-title":"Res. Vet. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"103890","DOI":"10.1016\/j.jevs.2022.103890","article-title":"Streptococcus equi culture prevalence, associated risk factors and antimicrobial susceptibility in a horse population from Colombia","volume":"111","author":"Gomez","year":"2022","journal-title":"J. Equine Vet. Sci."},{"key":"ref_11","first-page":"153","article-title":"Bacterial isolates from equine infections in western Canada (1998\u20132003)","volume":"49","author":"Clark","year":"2008","journal-title":"Can. Vet. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1136\/vr.d1725","article-title":"Seroprevalence of Streptococcus equi in working horses in Lesotho","volume":"169","author":"Ling","year":"2011","journal-title":"Vet. Rec."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e000187","DOI":"10.1136\/vetreco-2016-000187","article-title":"Streptococcus equi subspecies equi in horses in Israel: Seroprevalence and strain types","volume":"3","author":"Blum","year":"2016","journal-title":"Vet. Rec. Open"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"793","DOI":"10.1111\/evj.12834","article-title":"Respiratory disease and sero-epidemiology of respiratory pathogens in the working horses of Ethiopia","volume":"50","author":"Laing","year":"2018","journal-title":"Equine Vet. J."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2751","DOI":"10.1111\/jvim.15939","article-title":"Markers of long term silent carriers of Streptococcus equi ssp. equi in horses","volume":"34","author":"Pringle","year":"2020","journal-title":"J. Vet. Intern. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"7095","DOI":"10.3168\/jds.2020-19471","article-title":"Scoping review on clinical definition of bovine respiratory disease complex and related clinical signs in dairy cows","volume":"104","author":"Ferraro","year":"2021","journal-title":"J. Dairy Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1161","DOI":"10.2460\/javma.247.10.1161","article-title":"Predictor variables for and complications associated with Streptococcus equi subsp equi infection in horses","volume":"247","author":"Duffee","year":"2015","journal-title":"Am. Vet. Med. Assoc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1016\/j.cveq.2014.08.007","article-title":"New perspectives for the diagnosis, control, treatment, and prevention of strangles in horses","volume":"30","author":"Waller","year":"2014","journal-title":"Vet. Clin. N. Am.-Equine Pract."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1111\/jvim.15037","article-title":"Decreased clinical severity of strangles in weanlings associated with restricted seroconversion to optimized Streptococcus equi ssp equi assays","volume":"32","author":"Tscheschlok","year":"2018","journal-title":"J. Vet. Intern. Med."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"589","DOI":"10.2460\/ajvr.1991.52.04.589","article-title":"Field evaluation of a commercial M-protein vaccine against Streptococcus equi infection in foals","volume":"52","author":"Hoffman","year":"1991","journal-title":"Am. J. Vet. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"4861","DOI":"10.1016\/j.vaccine.2020.05.046","article-title":"Intramuscular vaccination with Strangvac is safe and induces protection against equine strangles caused by Streptococcus equi","volume":"38","author":"Robinson","year":"2020","journal-title":"Vaccine"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1136\/vr.147.20.563","article-title":"Investigations towards an efficacious and safe strangles vaccine: Submucosal vaccination with a live attenuated Streptococcus equi","volume":"147","author":"Jacobs","year":"2000","journal-title":"Vet. Rec."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1160","DOI":"10.1016\/j.vaccine.2015.01.019","article-title":"Vaccination with a live multi-gene deletion strain protects horses against virulent challenge with Streptococcus equi","volume":"33","author":"Robinson","year":"2015","journal-title":"Vaccine"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1111\/evj.13443","article-title":"Horses vaccinated with live attenuated intranasal strangles vaccine seroconvert to SEQ2190 and SeM","volume":"54","author":"Boyle","year":"2022","journal-title":"Equine Vet. J."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Boyle, A.G., Stefanovski, D., and Rankin, S.C. (2017). Comparison of nasopharyngeal and guttural pouch specimens to determine the optimal sampling site to detect Streptococcus equi subsp equi carriers by DNA amplification. BMC Vet. Res., 13.","DOI":"10.1186\/s12917-017-0989-4"}],"container-title":["Veterinary Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-7381\/10\/2\/78\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:11:23Z","timestamp":1760119883000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-7381\/10\/2\/78"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,20]]},"references-count":25,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["vetsci10020078"],"URL":"https:\/\/doi.org\/10.3390\/vetsci10020078","relation":{},"ISSN":["2306-7381"],"issn-type":[{"value":"2306-7381","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,20]]}}}