The prevalence of Streptococcus equi subsp. equi carriers in the Netherlands

R M A C Houben; E M Broens; M J Broekhuizen-Stins; M M Sloet van Oldruitenborgh-Oosterbaan; C van Maanen; J A P Heesterbeek

doi:10.1002/evj.70177

The prevalence of Streptococcus equi subsp. equi carriers in the Netherlands

R M A C Houben^*
, E M Broens
, M J Broekhuizen-Stins
, M M Sloet van Oldruitenborgh-Oosterbaan
, C van Maanen
, J A P Heesterbeek

^*Corresponding author for this work

Royal GD

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

BACKGROUND: Streptococcus equi subspecies equi (S. equi) carriers are thought to be important drivers for strangles outbreaks. Limited data are available on the prevalence of carriers in European horse husbandry settings.

OBJECTIVES: To estimate the prevalence of S. equi carriers among apparently healthy adult horses and ponies in the Netherlands.

STUDY DESIGN: Cross-sectional survey.

METHODS: The carrier prevalence in the Netherlands was estimated, detecting carriers by PCR analysis of three repeated nasopharyngeal lavages at weekly intervals. Bayesian methods were used for a true prevalence estimation.

RESULTS: One hundred and sixty-six horses on 86 premises were sampled. The posterior distribution gave a mean and median estimate for true prevalence of 2.0% and 1.6%, respectively, with a 95% credible interval of [0.1%, 5.9%].

MAIN LIMITATIONS: The target of 200 participants in the cross-sectional survey was not reached. The sensitivity of three repeated nasopharyngeal lavages for the detection of carriership remains uncertain.

CONCLUSIONS: The carrier prevalence estimate of 2.0% reported here is in the same order of magnitude as recent reports from other countries.

Original language	English
Journal	Equine Veterinary Journal
DOIs	https://doi.org/10.1002/evj.70177
Publication status	E-pub ahead of print - 26 Apr 2026

Bibliographical note

Publisher Copyright:
© 2026 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.

Funding

This study was partially funded by a grant from the Utrechts Universiteitsfonds.

Funders
Utrechts Universiteitsfonds

Keywords

Streptococcus equi
carrier
cross-sectional survey
horse
prevalence
strangles

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10.1002/evj.70177Licence: CC BY-NC

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@article{255de4963b8c490e8d7c77ba4371ebb6,

title = "The prevalence of Streptococcus equi subsp. equi carriers in the Netherlands",

abstract = "BACKGROUND: Streptococcus equi subspecies equi (S. equi) carriers are thought to be important drivers for strangles outbreaks. Limited data are available on the prevalence of carriers in European horse husbandry settings.OBJECTIVES: To estimate the prevalence of S. equi carriers among apparently healthy adult horses and ponies in the Netherlands.STUDY DESIGN: Cross-sectional survey.METHODS: The carrier prevalence in the Netherlands was estimated, detecting carriers by PCR analysis of three repeated nasopharyngeal lavages at weekly intervals. Bayesian methods were used for a true prevalence estimation.RESULTS: One hundred and sixty-six horses on 86 premises were sampled. The posterior distribution gave a mean and median estimate for true prevalence of 2.0\% and 1.6\%, respectively, with a 95\% credible interval of [0.1\%, 5.9\%].MAIN LIMITATIONS: The target of 200 participants in the cross-sectional survey was not reached. The sensitivity of three repeated nasopharyngeal lavages for the detection of carriership remains uncertain.CONCLUSIONS: The carrier prevalence estimate of 2.0\% reported here is in the same order of magnitude as recent reports from other countries.",

keywords = "Streptococcus equi, carrier, cross-sectional survey, horse, prevalence, strangles",

author = "Houben, \{R M A C\} and Broens, \{E M\} and Broekhuizen-Stins, \{M J\} and \{Sloet van Oldruitenborgh-Oosterbaan\}, \{M M\} and \{van Maanen\}, C and Heesterbeek, \{J A P\}",

note = "Publisher Copyright: {\textcopyright} 2026 The Author(s). Equine Veterinary Journal published by John Wiley \& Sons Ltd on behalf of EVJ Ltd.",

year = "2026",

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day = "26",

doi = "10.1002/evj.70177",

language = "English",

journal = "Equine Veterinary Journal",

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T1 - The prevalence of Streptococcus equi subsp. equi carriers in the Netherlands

AU - Houben, R M A C

AU - Broens, E M

AU - Broekhuizen-Stins, M J

AU - Sloet van Oldruitenborgh-Oosterbaan, M M

AU - van Maanen, C

AU - Heesterbeek, J A P

PY - 2026/4/26

Y1 - 2026/4/26

N2 - BACKGROUND: Streptococcus equi subspecies equi (S. equi) carriers are thought to be important drivers for strangles outbreaks. Limited data are available on the prevalence of carriers in European horse husbandry settings.OBJECTIVES: To estimate the prevalence of S. equi carriers among apparently healthy adult horses and ponies in the Netherlands.STUDY DESIGN: Cross-sectional survey.METHODS: The carrier prevalence in the Netherlands was estimated, detecting carriers by PCR analysis of three repeated nasopharyngeal lavages at weekly intervals. Bayesian methods were used for a true prevalence estimation.RESULTS: One hundred and sixty-six horses on 86 premises were sampled. The posterior distribution gave a mean and median estimate for true prevalence of 2.0% and 1.6%, respectively, with a 95% credible interval of [0.1%, 5.9%].MAIN LIMITATIONS: The target of 200 participants in the cross-sectional survey was not reached. The sensitivity of three repeated nasopharyngeal lavages for the detection of carriership remains uncertain.CONCLUSIONS: The carrier prevalence estimate of 2.0% reported here is in the same order of magnitude as recent reports from other countries.

AB - BACKGROUND: Streptococcus equi subspecies equi (S. equi) carriers are thought to be important drivers for strangles outbreaks. Limited data are available on the prevalence of carriers in European horse husbandry settings.OBJECTIVES: To estimate the prevalence of S. equi carriers among apparently healthy adult horses and ponies in the Netherlands.STUDY DESIGN: Cross-sectional survey.METHODS: The carrier prevalence in the Netherlands was estimated, detecting carriers by PCR analysis of three repeated nasopharyngeal lavages at weekly intervals. Bayesian methods were used for a true prevalence estimation.RESULTS: One hundred and sixty-six horses on 86 premises were sampled. The posterior distribution gave a mean and median estimate for true prevalence of 2.0% and 1.6%, respectively, with a 95% credible interval of [0.1%, 5.9%].MAIN LIMITATIONS: The target of 200 participants in the cross-sectional survey was not reached. The sensitivity of three repeated nasopharyngeal lavages for the detection of carriership remains uncertain.CONCLUSIONS: The carrier prevalence estimate of 2.0% reported here is in the same order of magnitude as recent reports from other countries.

KW - Streptococcus equi

KW - carrier

KW - cross-sectional survey

KW - horse

KW - prevalence

KW - strangles

UR - https://www.scopus.com/pages/publications/105036677396

U2 - 10.1002/evj.70177

DO - 10.1002/evj.70177

M3 - Article

C2 - 42036105

SN - 2042-3306

JO - Equine Veterinary Journal

JF - Equine Veterinary Journal

ER -

The prevalence of Streptococcus equi subsp. equi carriers in the Netherlands

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Bibliographical note

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Keywords

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