Equine strangles is another term for equine distemper. Strangles is a highly infectious disease that affects the upper respiratory tract of horses. It is caused by the bacteria Streptococcus equi. Strangles most often affects young horses, but can affect any horse that has not been vaccinated or had strangles before.
Strangles has an incubation period of 3-6 days, but occasionally horses will not show signs for up to 21 days. Loss of appetite and fever are followed by swollen pus filled lymph nodes and a runny nose.
The lymph nodes become abscessed with pus. The abscesses mature and drain in 10-14 days. This process can be sped up with the application of hot packs to help the abscesses to mature faster. Then they can be lanced and drained by a veterinarian.
A runny nose, swollen throat and pus filed lymph nodes make it difficult for the horse to breathe, thus the term ‘strangles.’ Horses may stand with an outstretched neck in order to breathe better. In severe cases the horse may need to have a tracheotomy.
A tracheotomy is a procedure where a hole is cut directly into the windpipe of the horse. This allows the animal to breathe air directly from the tracheotomy hole and bypass the clogged air passages all together. This is a temporary emergency procedure and the vet will close the tracheotomy hole when it is no longer needed.
Equine distemper is spread through contact with the pus, saliva and nasal discharge of infected animals. It can be passed directly from one animal to another or from contaminated water a troughs and common feeding areas and human contact with an infected horse to a healthy horse. Flies can also spread the bacteria from one animal to another. Infected horses should be quarantined.
The only treatment for strangles is complete rest and nursing care. The animal should be monitored to assure their ability to breathe. Antibiotics are not recommended except in very extreme cases. The use of antibiotics has been known to cause the abscesses to spread to other parts of the body. This is referred to as ‘bastard strangles’. Bastard strangles is much less common and has a higher risk of death.
Horses can be vaccinated for strangles but not during an outbreak. The vaccines only last for 6-12 months and must be given regularly to maintain coverage. Unfortunately the vaccines are not fool-proof. Up to 50% of vaccinated animals will still get equine strangles when exposed to the disease.
Not every horse that is exposed to strangles will contract the disease. The greater the exposure to equine distemper the higher the odds of coming down with the disease.
Foals and horses that are stressed are at more risk if exposed to the strangles bacteria. Stress can be caused from poor nutrition, ill health and long stressful transportation.