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Research article - Peer-reviewed, 2020

Markers of long term silent carriers of Streptococcus equiss p.equiin horses

Pringle, John; Venner, Monica; Tscheschlok, Lisa; Waller, Andrew S.; Riihimaeki, Miia

Abstract

Background Difficulty in detection of silent carriers ofStreptococcus equiis a key reason for its continued spread to immunologically naive groups of horses. Objective To determine whether clinical examination, markers of inflammation, or serology differentiate silent carriers ofS. equiin recovered comingled horses. Animals Ninety-eight warmblood yearlings and 72 unaffected mares on a large breeding farm (outbreak A), 38 mature Icelandic horses at a riding stable (outbreak B), and 27 mixed breed horses at a boarding stable (outbreak C). Methods Prospective observational study 6 months to 2 years after strangles outbreaks. Carriers were defined as any animal positive on culture or qPCR toS. equifrom nasopharyngeal lavage or guttural pouch endoscopy and lavage. Most horses had complete physical exams and 1 group included evaluation of white blood cell counts and serum amyloid A. Sera from all horses was tested for antibodies to antigens A and C ofS. equiusing an enhanced indirect ELISA. Descriptive statistics were calculated. Data were compared using pairedttests, Wilcoxon ranked test, chi square, or the Fishers exact test. Significance was set atP < .05. Results Apart from weanlings at 6 months in outbreak A, there was no significant association between any clinical markers or serology with carrier state (P= .06-1). Moreover, 3/12 culture positive carriers were seronegative toS. equi. Conclusions and Clinical Importance Silent carriers ofS. equido not differ clinically or on markers of inflammation to their noncarrier herd-mates. Moreover, serology alone will not distinguish carriers in comingled horses.

Keywords

antigen A; antigen C; silent carrier; equine; iELISA; infection

Published in

Journal of Veterinary Internal Medicine
2020, volume: 34, number: 6, pages: 2751-2757
Publisher: WILEY

Authors' information

Swedish University of Agricultural Sciences, Department of Clinical Sciences
Venner, Monica
Equine Veterinary Clinic Destedt
Tscheschlok, Lisa
Equine Veterinary Clinic Destedt
Waller, Andrew S.
Animal Health Trust
Swedish University of Agricultural Sciences, Department of Clinical Sciences

UKÄ Subject classification

Clinical Science

Publication Identifiers

DOI: https://doi.org/10.1111/jvim.15939

URI (permanent link to this page)

https://res.slu.se/id/publ/108645