Strangles is a highly contagious bacterial infection of the upper respiratory tract in horses.  It is caused by the bacteria Streptococcus Equi Equi.  This troublesome disease can cause horses to become very sick and in small number of cases can be fatal.  It can also lead to yards being closed and movement of horses being restricted until the disease has been eliminated from the yard, causing significant financial strain.  This devastating respiratory infection is found throughout the UK.

Clinical signs:

The clinical signs associated with Strangles can include:

  • High temperature/ pyrexia causing horses to be dull,  depressed, not eating or drinking
  • Purulent nasal discharge
  • Coughing and difficulty breathing
  • Enlargement of the lymph nodes around the head and neck which can lead to abscessation, bursting and discharge of highly infectious material or pus

In some case’s the horse can display all the above signs but in a lot of cases they will only show one or two clinical signs.  If your horse displays any of the above signs Equine Health Direct would recommend speaking to your veterinary surgeon immediately.


To confirm that your horse has contracted Strangles, a positive culture of the bacteria (Strep. equi equi) from swabs of nasal discharge, pus discharging from lymph nodes that have abscessed or swabbing the back of the throat is required.

Blood Samples:

Blood samples will tell you if the horse has recently encountered the bacteria causing Strangles.  The blood sample is looking for antibodies against the bacteria.  Further investigations would need to be done if there are no clinical signs of infection and the blood sample strongly suggests that the horse has been in contact with the bacteria.  Further investigations will include endoscopy of the guttural pouches at the back of the throat and samples being taken from there and sent to the lab for culture to determine if the horse is infected or remains infected.


Treatment of this infection can vary from case to case and your veterinary surgeon will provide you with expert advice on what is the most appropriate way to treat the case.

  • Hot compressing or your veterinary surgeon lancing enlarged lymph nodes to allow drainage of pus and infection can also be done.
  • Antibiotics can be used to treat the disease.  Anti-inflammatories can help to reduce temperatures, alleviate pain and discomfort and make your horse feel more comfortable.  Your veterinary surgeon will advise which treatment is appropriate for your horse.


The following will help you manage this disease:

  • Recognising the clinical signs of the disease
  • Prompt notification and examination of your animal by your vet
  • Quick accurate diagnosis

The disease is spread by direct contact between infected animals and other horses.  This can happen through:

  • horse to horse contact
  • contact through yard, riding and grooming equipment
  • humans and animals (cats & dogs) moving between different horses on the yard.

If you suspect or have had it confirmed by your vet that a horse is infected with Strangles:

  • Strict isolation and hygiene rules must be put in place and the yard must be closed to any horse movement on or off the yard.
  • Isolate the infected horse immediately and closely monitor the horses that may have been in contact with it.
  • Monitor the temperatures of the remainder of the horses on the yard twice a day and isolate any cases that spike a fever (over 38.5oC)
  • Isolated horses are cut off from the remainder of the yard and items like mucking out equipment, tack, grooming items must only be used with isolated horses.
  • One person should be designated to deal with the infected horse and they should not have any contact with the remainder of the yard
  • Disinfect hands, boots, clothing etc upon leaving isolation
  • Make sure that everyone on the yard is informed of the situation and is working towards the goal of making the yard disease free. It will take several months for the yard to be confirmed as disease free but can be shorter if everyone on the yard works together.

Further testing of horses on the yard will determine whether the yard is disease free or not. The recommendation is to test 4 weeks after the last positive case has stopped displaying clinical signs of Strangles.

Preventing the disease on livery yards:

New arrivals should be quarantined for a minimum of 2 weeks upon arrival at a new yard.  They need to be isolated for this long because the incubation period of the disease is 3- 14 days.  New arrivals should arrive to quarantine with a negative blood sample result, taken at the previous yard indicating that they have not come in to contact with or are carrying the disease.

“Carrier” horses:

A difficult situation arises when a horse becomes identified as a “carrier” of the disease.  This means that the horse carries the bacteria but does not display any clinical signs of the disease.  These horses need to be identified, isolated and treated as soon as possible because they can act as a source of persistent infection on a yard.  Treatment of these cases involves repeated flushing of the guttural pouches with antibiotic solution and repeated testing until the horse has provided a negative result.

If you have any questions or concerns about Strangles we strongly recommend contacting your own veterinary surgeon.