Equine Strangles

Strangles (Streptococcus equi) is an extremely contagious bacterial infection specific to horses.

Strangles (Streptococcus equi) is an extremely contagious bacterial infection specific to horses. The most common symptom is a noticeable swelling of the lymph nodes in the throat, which can lead to a restriction of the horse's ability to breathe creating "strangled" breathing sounds, hence the common name for the disease. This article will be broken down into four basic sections in an effort to thoroughly explain the condition: Signs & Symptoms, Treatment, Complications, and Prevention.

Signs and Symptoms:

When it comes to horses, it is always wise to be well aware of what is normal for your horse(s). The beginnings of an illness can be very subtle, and the better you know your horse the sooner you will be able to tell when something is wrong. An easy way to get into the habit of frequently monitoring the health of your horse is to do a simple vitals check at every meal. Does your horse look alert? Comfortable? Normal? The more often you check, the more likely it will be that you will catch something like Strangles in its early stages and be able to treat it quickly and effectively. Horses infected with Strangles can display a combination of symptoms or just one. The most common symptoms are: a lack of appetite, fever (normal temperature should be around 99.6-100.8, anything over 104 is considered unsafe), listlessness and a distinct swelling of the lymph nodes in the throat area. Strangles generally effects the upper respiratory tract and head area of the horse causing a swollen throat, swollen and often pus filled lymph nodes, nasal discharge, difficulty breathing, and cold like symptoms.


If you have a horse displaying any of the above symptoms isolate the animal from other horses on the premises and contact your veterinarian. Your veterinarian can take a nasal swab of your horse's mucous and perform a Gram positive test for the Streptococcus equi bacteria, if positive, the sample taken from your horse will fluoresce purple when introduced to a special Gram stain created to specifically identify that type of bacteria. Once Strangles has been confirmed, treatment is relatively simple. In most cases the main form of treatment is to simply monitor the horses vital signs including temperature, heart rate, and respiratory rate. The disease is self-limiting, and can generally be fought off by the immune system of most healthy horses without outside aid. The use of antibiotics is generally not recommended. By the time the disease manifests its self, antibiotics will no longer be effective at eradicating the infection. In addition, many veterinarians feel that antibiotics will do more harm than good by killing off beneficial bacteria the horse needs to fight the Strangles infection. The most important "treatment" is simply making the horse as comfortable as possible, encouraging it to eat and drink, and keeping a very close eye out for any possible secondary complications. It may also become necessary to lance and drain extremely infected and swollen exterior lymph nodes.


Although complications are rare, they can occur. One major complication results from the extreme swelling of internal lymph nodes in the throat. If the swelling reaches a point where the airways are severely compressed, the horses ability to breath can become severely restricted. In this case, a tracheotomy will have to be performed (this involves putting a hollow tube down the horses throat to forcefully create an airway). Another risk involved with the internal swelling of lymph nodes in the throat is the possibility that they will rupture, and the pus will drain into the horses lungs creating the possibility of secondary infections such as pneumonia. If this should happen, the secondary infections will be treated according to their severity and may require a round of antibiotics.

The most severe complication related to strangles generally occurs in horses with weakened or immature immune systems. When the immune system is weak, the bacteria can spread through the horse's entire body creating a systemic infection. Such an infection is generally called Bastard Strangles, and symptoms include extreme depression and lethargy and a very high fever. Once the disease has gone systemic, it is generally fatal.


If you have multiple horses, it's very important to separate an infected horse from the healthy ones. Strangles is passed from horse to horse via nasal secretions and puss from ruptured lymph nodes. It may take 7-14 days for the disease to manifest and an infected horse to show symptoms, so it is also a good idea to isolate any horses that have come into contact with a known infected horse. A quarantine of the farm should be initiated and movement of horses onto or off of the farm should be restricted for 14-21 days.

The disease can also be spread via contaminated water buckets/troughs, brushes, stalls, and any other equipment which may have come into contact with an infected horse. Do not share your equipment with others, and sanitize any equipment used by an infected horse.

If you are at a public boarding facility, or using a stall at a public show barn, it is a good idea to bleach the entire stall (including walls, floor, and ceiling), hay rack, water bucket, and any other equipment in the stall prior to placing your horse in the stall.

Avoid letting your horse come into contact with strange horses. Practice good hygiene (washing hands, etc.) when working with new horse, or after being in contact with horses from another stable.

The information in this article is not meant to take the place of proper veterinary care. If you suspect that your horse is ill, contact your vet immediately for proper diagnosis of the illness and to determine the best course of treatment.

© High Speed Ventures 2011