Disease control program for strangles - Pilotstudy for risk assessment in riding schools

Strangles – A Threat to the Equine Industry

Strangles, a contagious bacterial infection caused by Streptococcus equi subspecies equi, is a notifiable disease that affects over 70 equine facilities in Sweden each year. It is a significant challenge for horse management and is listed in the National Surveillance Plan (NÖP).

A horse with strangles typically develops fever, nasal discharge, and swollen lymph nodes that may develop into abscesses. In severe cases, complications such as pneumonia, abscesses spreading throughout the body (“bastard strangles”), or blood vessel inflammation (anasarca) can occur. These complications are often life-threatening. For the equine industry, strangles leads to prolonged disruptions, significant economic losses, and suffering for horses and their owners.

Facilities affected by strangles are required to close until all horses have recovered, followed by a quarantine period of an additional 3–6 weeks. It is therefore crucial to identify risk factors and develop effective strategies to prevent and control strangles.

________________________________________

Project Objectives and Goals

This project aims to investigate which horses pose the greatest risk for spreading strangles and how the disease can best be prevented. The focus will be on studying newly acquired horses, particularly riding school horses, and analyzing their background and any prior exposure to strangles.

No previous study has investigated the seroprevalence (the percentage of horses with antibodies) within these groups in Sweden. The project will also evaluate the level of biosecurity at riding schools and contribute concrete tools for improving infection control practices.

________________________________________

Expected Outcomes

1. Seroprevalence in the Risk Group

The proportion of newly acquired riding school horses with antibodies against Streptococcus equi will be mapped. This will provide insight into how common exposure to the infection is within this group. Stored samples can also be used in future studies of other equine diseases.

2. Risk Factor Analysis

Identification of risk factors within the group of newly acquired horses. This analysis will provide an overview of the current biosecurity measures at riding schools and highlight areas for improvement.

3. Outbreak Analysis

Investigating the impact of strangles outbreaks on horse health, economy, and operations will provide essential knowledge for future risk assessments.

4. Guidelines for Quarantine

Concrete recommendations for the design of receiving and quarantine facilities as well as protocols for managing imported, newly acquired, or sick horses.

5. Vaccination Recommendations

Evaluation of how vaccination against strangles can be implemented at riding schools to reduce the risk of outbreaks.

6. Communication and Education

Development of information materials and training programs for horse owners and riding schools. The aim is to provide practical advice on risk management and preventative measures.

________________________________________

Importance for the Equine Industry

By identifying risk factors and developing effective preventative measures, the project can contribute to:

• Reduced risk of strangles outbreaks.

• Improved horse health and welfare.

• Increased profitability and competitiveness for riding schools and other equine facilities.

• Opportunities to negotiate lower insurance premiums for facilities that follow recommended safety protocols.

The project will also give the equine industry a clearer understanding of its vulnerabilities and challenges. A structured risk analysis will create the conditions needed to better manage contagious equine diseases in the long term.

________________________________________

Summary

By investigating the risk of strangles in newly acquired horses and developing tools for infection control, the project aims to strengthen the equine industry in Sweden. The results will be used to improve biosecurity, create guidelines for quarantine and vaccination, and provide the equine industry with better tools to prevent and manage future outbreaks.