Strangles is caused by the bacterial Streptococcus equi, an infection which has affected horses almost since the antiquity. The number of cases is steadily growing. The disease is similar with, tonsillitis/paratonsillitis/scarlet fever in humans, caused by Streptococcus pyogenes. In Sweden, strangles is one of few bacterial infections in horses, which must be reported to the authorities.

The infection ceases after about a month. The infection is very contagious and requires full isolation of an affected facility. Due to the highly contagious character of this disease, a rapid diagnosis combined with isolation of suspected cases is the most effective step in reducing the outbreak. Approximately 5 procent of infected horses develop life threatening complications or death.

Moreover, antibiotic therapy has failed to cure the disease due to, abscess formation which preventing i.e. penicillin to reach and kill the bacteria. Another important risk factor for spreading the disease is the persistent “healthy” bacterial carriers following spontaneous infections.

The economical impact by closing stables in trotting and riding companies might put the companies into insolvency.

A safe and effective vaccine program would therefore be the absolutely best tool for controlling the disease in the future.