One confirmed case and five suspected cases of the equine bacterial infection strangles were reported by the Mare and Foal Sanctuary on April 27th at its rehabilitation facility, Honeysuckle Farm in Newton Abbot, England.  

Beautiful horses
Public domain image/Dusan Bicanski

This outbreak was discovered during a routine examination of the six horses upon arrival at the facility after being rescued by the charity.  The infected animals had already been placed into quarantine upon admission to the facility, as the charity follows a strict process of segregation and screening.  It is highly unlikely that this outbreak will spread into the other herds at this facility or into the surrounding community, as the charity has restricted the arrival, departure or relocation of any animals at this facility until all animals are completely cleared of this disease.

Strangles poses no risk to humans, but is highly contagious and common among horses.  Strangles is caused by infection with Streptococcus equi subspecies equi.  Symptoms include fever, diminished appetite, nasal discharge (that begins clear and turns purulent) and enlarged submandibular lymph nodes that can become abscessed.  It is in the obstructed breathing caused by enlarged lymph nodes and in rare cases death by suffocation that the disease received its name.  In most cases, infection with S. equi self-resolves, but this disease has a death rate of about ten percent, usually from complications involving spread beyond the head and neck, including pneumonia.

Transmission occurs by direct contact between animals and via fomites or water sources.  Treatment can include chemotherapy with antibiotics if initiated in the very early stage of the disease or as post-exposure prophylaxis; otherwise, initiation of antibiotic treatment is not recommended due to evidence that it can prolong infection or inhibit formation of post-infection immunity.  As about twenty percent of cases become asymptomatic nasal carriers, vaccination is the considered the best method of control.

Steven Smith, M.Sc. is an Infectious diseases epidemiologist