Strangles is a highly infectious disease caused by the bacteria Streptococcus equi. It is found only in equine species (horses, ponies, donkeys, and mules) and presents no danger to people and other pets.
Strangles is an infection of the upper airway (nose and throat) and the lymph nodes in the area of the throat. It produces nasal discharge and may cause swollen lymph nodes around the throat which can break open and cause the patient to stop eating and feel depressed. The disease gets its name from the rasping breathing which can occur from swelling around the throat.
Strangles is highly contagious and spreads quickly through a herd. It is passed by the mucous discharge from the nose and draining abscesses of sick horses. The spread can be by direct contact from horse to horse, eating or drinking from the same containers, grazing the same pasture, sharing grooming tolls and tack, or breathing the aerosol spray from a coughing horse. It is also very important to realize that is can be carried by mucous on the hands, clothing, or shoes, or a person moving from an infected horse or barn to another.
Once a horse catches the disease the best treatment is to give good nursing care until the involved lymph nodes abscess and drain. This would include butazolidin to help keep down the temperature and make the horse feel better, hot packs and poultices on swollen lymph nodes, and keeping the nose and nodes clean. Antibiotics are not recommended once the horse gets sick until he starts to get over the disease and develops an immunity. Once the horse has begun to get over the disease the antibiotics may help to resolve the infection a little faster.
It takes about one to two weeks for a horse to develop the disease from the time of infection. The disease lasts for ten to fourteen days. The horse can be contagious for at least 30 days after being sick. The disease is worse in younger animals and affects one hundred percent of horses within a herd which have not developed immunity. Once they have had the disease they develop a good immunity which can last for several years. While it is usually a fairly mild disease, it can become complicated in some individuals and involve lymph nodes throughout the body ("bastard strangles") or turn into pneumonia or other systemic diseases which can be fatal.
Prevention is best accomplished by quarantining any new additions to a herd for two weeks. This is difficult in most barns. An intranasal vaccine which should be given at six months of age and bolstered in three weeks. Annual boosters are then required. The immunity which this vaccine produces is not perfect, but it may prevent disease from casual contact and lesson the severity if they do get it.
Once the disease has been identified in a herd the best approach is to close the herd from any entering or exiting until it has resolved. Any individuals that have been sick with only a runny nose but no draining abscesses should be isolated for one month. Horses with draining nodes should remain on the farm for at least 30 days after drainage has stopped.
After the last case has resolved all stalls should be stripped, the walls and buckets cleaned with a disinfectant, and the floors heavily limed. Any new horse coming into the herd should have the two-
Strangles is a nasty disease but it is always in the horse population and can break out anywhere. The important thing is that when it does appear to treat it responsibly and to try to minimize its spread.