Strangles; What YOU Need to Know


What is it?

Strangles is a highly infectious bacterial infection in horses of the upper respiratory tract. Infection is by ingestion or inhalation with subsequent localisation in the lymph nodes in the area of the jaw and neck. It is most often seen in horses under 5 years of age and after initial exposure, signs develop in 3 to 10 days. Morbidity (number clinically infected) can often be 100%, but Mortality is usually less than 5% and where death occurs it is usually from secondary pneumonia.

Signs and Symptoms

  • Swelling of the lymph nodes/glands of the lower jaw
  • Loss of Appetite
  • Lethargy
  • Nasal Discharge
  • A fever over 40 degrees centigrade


How Can I Prevent Strangles in My Horse?

Personal hygiene is of utmost importance around infected horses. ( Washing hands, using hygiene gloves, disinfecting utensils etc). The disease is spread by nasal discharge, saliva, fluid from abscesses and sharing troughs, or by contaminated grooming utensils, feed bins and rugs. Take care at events and keep your horse separate from others (common sense) and wash hands and utensils often if in contact with other horses of unknown origin.


The common vaccination for Strangles is Equivac S. This is a series of vaccinations with an initial course of 3 vaccinations 2 weeks apart followed by 6 monthly to annual vaccinations. There is also an intra-nasal vaccination named Pinnacle. This vaccination is given (after reconstitution) into one nostril with a booster 4 weeks later and an annual vaccination thereafter.

The vaccination does have side effects ,but these are rare. Vaccination does cause a drop in the immune system which may make the horse prone to other diseases or infection if exposed. If you have had your horse vaccinated for strangles and it has completed its entire course and you keep up your vaccinations, your horse should be protected. If you horse has had vaccinations randomly and the vaccinations have run out by over 6 months then you should start the whole course again.

Diagnosis and Treatment

To have strangles diagnosed you need a veterinarian to take a nasal swab of your horse. This swab will determine if it is positive for strangles. As already mentioned, it will be 3-10 days after exposure before clinical signs appear and it will be contagious to other horses during this period and will continue to be contagious through the shedding of bacteria for approximately 2-3 weeks after first clinical signs. It some cases shedding of bacteria may be longer. This is why repetative nasal swabs are required to determine conclusively that bacterial shedding has stopped (generally 3 negative swabs 10 days apart).

The treatment for Strangles may include antibiotics and will include isolation to not only stop the spread of strangles. Other supportive treatment may also be required.

If you have any concerns that your horse may well be ‘off colour’ or showing signs of Strangles then it is vital you keep your horse isolated for a vet to examine and possibly take samples to be sent to a diagnostic laboratory.

If you have further questions please feel free to talk to any of our vets and staff.

The Vet Centre, Richmond (5445566) and Motueka (5288459)