Strangles is a bacterial infection of the upper respiratory tract that commonly affects the submandibular lymph nodes and is caused by Streptococcus equi ssp equi. It is typically a disease of younger horses, but older horses can also become infected. Horses infected with strangles are susceptible to a condition known as bastard strangles (abscess elsewhere in the body – abdomen or chest) and /or pupura hemorrhagica (severely swollen legs).
Isolation of infected horses from other horses is very important. Horses with strangles are highly contagious. The disease can be transmitted by nasal discharge, drainage from abscesses, and any secretions from the upper airway. Humans, equipment, buckets, feeders, etc can all contribute to the spread of the disease. It is very important to wear gloves when handling infected horses, keep all equipment (buckets, feeders, brushers, etc) separate, and clean with diluted bleach (1:10 dilution). It is also important to minimize contact with infected horses; by performing treatment and feeding only; handling infected horses last. Common water sources should be disinfected daily. It is also important to avoid sharing of water sources by horses that are infected.
Horses who are housed near infected horses should have their temperatures monitored daily (normal is 99-101.5 F). Monitor horses on the property for any nasal discharge, swellings under the jaw, coughing, decreased appetite, or increased temperature as these can all be clinical signs of strangles. Strangles has an average incubation period of 2 weeks, meaning that once a horse has been exposed it may not develop the condition until 2 weeks later.
Horses infected or exposed to strangles should have daily monitoring of temperature, respiratory rate, and hot compresses on the submandibular (located in the throat latch area) area if needed. Because strangles is a complex disease you should contact your veterinarian for additional instructions.