Strangles – IN BOAH

Facts About Strangles & Biosecurity to Prevent Strangles

From the Indiana Board of Animal Health (printable pdf)

Facts About Strangles

Strangles is among the oldest most important diseases of equine. The name comes from the horse making strangled breathing sounds resulting from enlarged lymph nodes of the neck and head. Strangles can affect horses, donkeys and mules of all ages, but usually those younger than two years of age. Foals younger than four months are usually protected by passive immunity through the colostrum.

Clinical Signs

  • Initial signs include mild lethargy or depression, slight cough, fever of 102F to 103F and clear watery discharge from the nose
  • Later signs include thick yellow discharge, trouble swallowing, loss of appetite and enlarged lymph nodes in the lower jaw


  • Exposure to nasal secretions (sneezing, coughing and nose-to-nose contact)
  • Exposure to pus of draining abscesses
  • Flies and contaminated equipment such as water buckets, hoses, feed troughs, pitchforks, feed, stalls, fences and tack can spread bacteria
  • A person handling an infected horse can carry the organism on clothing, boots or unwashed hands

Contributing Factors

  • Overcrowding
  • Stress
  • Inadequate housing
  • Poor sanitation
  • Poor nutrition
  • New animal additions

Incubation Period

  • As short as four days but as long as 12 to 14 days
  • 20 percent of horses continue to shed the bacteria for a month after all clinical signs are gone


  • Isolate infected horse in a warm, dry environment
  • Monitor temperature regularly
  • Feed soft food if needed
  • Apply hot compresses to abscessed lymph nodes to promote rupture and drainage
  • Clean and flush draining lymph nodes to prevent infection

Biosecurity to Prevent Strangles

  • Wash hands after handling each horse.
  • Use boot washes to scrub manure from shoes prior to entering each stall (walk-thru foot baths are not effective)
  • Sharing equipment (e.g., buckets and tack) among horses should be avoided(shared equipment must be cleaned, sanitized and drained between each use). Ideally, each horse should have its own equipment that is not shared.
  • Avoid nose-to-nose contact between horses
  • Limit people entering the barn to only those who are necessary
  • Clean and disinfect stalls between each occupant
  • Vaccination should be part of an ongoing preventative program but is not advised for horses that have been exposed to or are incubating the disease. Vaccination does not prevent strangles, it reduces severity and minimizes spread.
  • Keep hose nozzles out of the water buckets and troughs. The practice of submersing the hose nozzle has been identified as a major factor in outbreaks in large stables.
  • Control flies and other pests that can carry bacteria from horse to horse