Strangles is not an uncommon disease in horses, is very contagious, and can cause lots of problems when it occurs. Strangles causes an upper respiratory infection in which abscesses can be found in the lymph nodes under the jaw and in the throat area. However, some horses can develop internal abscesses that can be difficult to treat. Since the disease is quite contagious, infected horses must be quarantined until they are proven clear of infection. In many states, strangles requires veterinarians to report the case to animal health authorities, although that is not the case in Texas at this time. Some horses can remain carriers of the disease for months and even years and not show clinical symptoms, but can transmit the organism to susceptible horses. Usually it’s a disease of younger horses.
One method of trying to prevent the disease is vaccinating with a bacteria infused in the nasal cavity, not with a needle but with a pipette. However, lots of horses do not like this material infused in their nose, so some vets give the vaccine in the mouth even though until now this method has not been studied. Some vets also believe the vaccine may work better given orally rather than intranasally.
Recently, some researchers at Kansas State tested the effectiveness of the vaccine by giving it to some horses orally and some in the nose. Results indicated both routes of entry were effective at stimulating immunity against the disease. However, the magnitude of the response was greater giving the vaccine in the nose as it was intended. The vaccine can cause reactions if the horse has a high level of immunity against the bacteria when it is given, so ask your vet about their opinion on vaccinating your horse for strangles.