Strangles is a highly contagious disease of the respiratory tract and the lymph nodes primarily surrounding the throat. The disease is found worldwide in horses of all ages, although younger horses are most susceptible.
Strangles is caused by the bacteria Streptococcus equi, which may be transmitted during a horse's contact with discharges from the lymph nodes or nostrils of infected horses or by contact with equipment used on infected horses. Infection typically causes very high fever, loss of appetite, thick mucus and pus-like nasal discharge, and swollen or abscessed lymph nodes surrounding the throat.
Strangles usually responds to attentive nursing and -- in some cases -- antibiotics. Barring complications such as "bastard strangles," horses usually survive this infection. Horses with bastard strangles get abscesses in such places as the brain, abdominal cavity, and chest. With such complications, a horse may die from infection of the central nervous system, infection of the abdominal cavity, pneumonia, heart disease, sepsis, or overwhelming infection of the blood stream, and asphyxiation caused by the compression of the pharynx or larynx by swollen lymph nodes.
Strangles is best prevented by the strict isolation of horses thought to have the disease, and is prevented or ameliorated by vaccination. Vaccination is recommended especially for horses living in or traveling to areas in which the disease is endemic.
