Strangles is one of the common terms for the upper respiratory infection in horses caused by the bacteria Streptococcus equi or Strep equi for short. It is also sometimes referred to as equine distemper. A highly contagious disease that occurs worldwide, Strangles has recently been added to the USDA’s National List of Reportable Animal Diseases which means that veterinarians (and others) are required by law to notify state and federal officials if the disease is diagnosed or even suspected. It can occur in horses of any age although young horses seem to show more severe clinical signs and recover more slowly. The prognosis is good in that Strangles is rarely fatal but complications occur in approximately 20% of cases. These complications include the spread of infection from the head and neck to other parts of the body (metastatic or “bastard strangles”) and autoimmune conditions that affect the muscles, heart, and kidney as well as potentially lead to “purpura hemorrhagica” a syndrome that includes edema and capillary bleeding.
The incubation period for Strangles is 3 to 14 days, with the first sign of illness being a fever for 24 to 48 hours before showing any other classic signs:
A collection of experts in the field of infectious diseases of the horse has recently updated the veterinary recommendations for diagnosing Strangles. Hopefully, recent technological advances in the diagnostic testing of S. equi will make it easier to identify this bacteria sooner and with more certainty.
Since Strangles is a bacterial disease, it might seem obvious to reach for antibiotics as the first line of treatment. However, the use of antibiotics in this particular infection is controversial, because they may be unnecessary in mild to moderate cases with no complications and potentially even lead to problems.In most situations, simple supportive care while the disease runs its course may be best. This includes rest in a comfortable, clean, well-ventilated, and dry environment that is neither too hot nor too cold as well as soft, moist, tasty food of good quality. Both food and water should be easily accessible because the head, throat, and neck of horses with Strangles may be painful and they may be reluctant to stretch all the way down to the ground. Severely affected horses or those with complications may be candidates for antibiotics and other treatment at the discretion of the attending vet.