An introduction to the disease
‘Strangles’, caused by infection with the bacterium Streptococcus equi (S. equi), remains one of the most commonly diagnosed and important infectious diseases of horses world-wide. In the first half of 2007 the Animal Health Trust diagnostic laboratories analysed almost 8,000 samples from suspected strangles cases in the UK (Link to diagnostics webpage).
The disease is characterised by pyrexia (body temperature of over 39oC) followed by profuse nasal discharge and abscessation of the lymph nodes of the head and neck. The swelling of the lymph nodes in the head and neck may, in severe cases, restrict the airway and it is this clinical feature that gave the disease ‘strangles’ its name.
Nasal discharge characteristic of strangles.
Submandibular lymph node abscess.
A foal suffering from strangles with a respiratory obstruction.
Abscesses occasionally form in lymph nodes and body organs distant from the head and neck in a severe condition known as ‘bastard strangles’. S. equi infection (in common with other streptococcal infections in horses) may also trigger the immune complex disease purpura haemorrhagica associated with leakage of blood vessels and organ failure, which is often fatal.
Two cases of ‘Bastard strangles’
Characteristic signs of purpura haemorrhagica
