What is Strangles??Strangles is an infection caused by the bacteria Streptococcus equi ssp.The infection spreads by direct horse-to-horse contact or by humans, tack, drinking troughs, fences and from the environment contaminated with the infectious discharge.Typically the horse develops a fever (high temperature, >38.3*C) and swollen lymph nodes which abscess and rupture.equi.