What is strangles?
Strangles is a contagious bacterial infection of the horse’s upper respiratory tract. It is caused by the bacterium Streptococcus equi and is the most commonly diagnosed equine infectious disease.
How is strangles transmitted?
Strangles is spread by two routes:
- Direct contact – horse to horse contact
- Indirect contact – sharing feed buckets, tack, stable equipment. It can also be spread through contaminated hands, shoes etc.
Some horses that have recovered from strangles can become persistently infected and carry Strep. equi in their guttural pouch. These horses will be clinically well but can intermittently shed the bacterium during periods of stress and infect other horses.
- High temperature
- Nasal discharge
- Poor appetite
- Swollen lymph nodes of the head
- Death – although rare, a small number of horses can develop ‘bastard strangles’ where the infection spreads to other parts of the body.
Most clinical signs will take 3-14 days after exposure to show. Horses may show one or several of the above signs.
There are several options for diagnosing strangles and your vet will choose the best option for you:
- Blood Sample – this will detect antibodies (Ab) to the infection but not the organism itself. False negtives and positives can occur. Newly exposed horses can take 2 weeks for Ab to be detected and these may be detected for up to 6 months after exposure.
- Swabbing – Three nasopharyngeal swabs taken at weekly intervals or swabbing pus from burst abscesses to detect the bacterium.
- Endoscopy – this is the ‘gold standard’ for diagnosing and involves taking guttural pouch washouts to test for the bacterium. This can also determine if a horse is a carrier.
Treatment will vary according to the horses clinical signs. Infected horses should be isolated and movement on and off the yard stopped. Contact your veterinary surgeon immediately who will help advice on a quarantine protocol and treatment strategy.
Key steps can help prevent strangles outbreaks in the future:
- When away from home only use your own water bucket etc. Try to avoid direct contact with other horses.
- Blood sample for the strangles Ab before moving to new yards.
- Quarantine new arrivals to yards for a minimum of 2 weeks.
- Blood sample for the strangles Ab during vettings.
- Vaccination – does not prevent strangles but reduces clinical signs.
Will give a positive result on a strangles Ab blood test.
Often side effects associated with the vaccine.
Frequent booster vaccinations required.
The above information is presented for a basic guide only. If you are suspicious your horse has strangles contact your veterinary surgeon for further advice.