Biosecurity and protecting your horse from strangles

Dr. Amber Itle
Washington State Veterinarian 

This week, a Snohomish County horse that recently attended a show in Whatcom County was diagnosed with strangles, Streptococcus equi, an endemic bacterial infection that is rarely fatal, but as the name suggests, can affect a horse’s respiratory system. 

There is no evidence the horse was contagious at the time or that it contracted the disease at the show.  

Since January, there have been reports of six other confirmed, laboratory-diagnosed cases of strangles in Okanagan, Clallam, Kitsap, and Pierce counties.

Private veterinarians usually manage the strangles cases reported to the Washington State Veterinarian’s Office, including imposing self-quarantine, implementing biosecurity measures, and executing testing protocols. WSDA field veterinarians contact those veterinarians to monitor these cases and provide support, including issuing official quarantine orders in some cases. 

When a quarantine is in effect, no horses are allowed to move on or off the premises, attend horse shows, or travel. It is actually against the law to expose other animals to contagious, infectious, or communicable diseases.

How to protect your horse against strangles

Any time you attend a show, WSDA recommends monitoring horse’s body temperatures twice a day and isolating horses for up to three weeks to monitor for disease. Oftentimes, fever will precede illness and early detection can help prevent disease transmission. The incubation period (time of exposure to time of clinical signs) can range from 3-14 days. While strangles is a concern to many horse owners, there have also been several cases of Equine Herpes Myeloencephalopathy reported in California, a potentially fatal viral disease showcasing why biosecurity practices are critical for horses that attend exhibitions or other events.  

Strangles is rarely fatal and the prognosis for recovery is usually very good with proper care. Symptoms include:

• Fever
• Abscesses in the mandibular lymph nodes
• Nasal discharge that can include thick white and yellow mucus
• Inflammation of the throat
• Difficulty swallowing
• Wheezing
• Coughing
• In rare cases, bleeding from the capillaries

Good biosecurity practices are the best defense against the disease. The Equine Disease Communication Center’s “What is biosecurity?” offers excellent recommendations. 

The EDCC also recommends the following:

• When possible, isolate new horses for up to three weeks when they are being introduced to a new facility. 
• If you have handled an infected animal during an outbreak, avoid coming in contact with susceptible animals. 
• Wear protective clothing, avoid using the same equipment on multiple animals, and disinfect both your hands and equipment when moving between animals.

This “Strangles Fact Sheet” from the EDCC has more information on this disease, tips and suggestions.

Remember to notify WSDA if you become aware of a reportable disease by visiting our “Reportable Diseases” webpage.

Practice good biosecurity to protect your horse from strangles

Dr. Amber Itle
Washington Assistant State Veterinarian 

Strangles in horses, or Streptococcus equi infections, is a contagious disease endemic in Washington, but not usually fatal. Still, it is a reportable disease, and several cases have been reported recently to the Washington State Veterinarian’s Office.

Since the end of April, there have been reports of 16 confirmed, laboratory-diagnosed cases of strangles at five locations in King, Snohomish, Chelan, Yakima, and Thurston counties.

All are being managed by private veterinarians who have imposed self-quarantine, implemented biosecurity measures, and executed testing protocols. WSDA has been in contact with those veterinarians to monitor these cases and provide support.

WSDA can write quarantines to stop the movement of horses in cases where barns don’t comply with the instructions of a private veterinarian, but that has not been necessary in any of these recent cases because all are complying with their self-imposed quarantines.

When a quarantine is in effect, no horses are allowed to move on or off the premises, attend horse shows, or travel. It is actually against the law to expose other animals to contagious, infectious, or communicable disease.

Strangles is rarely fatal and the prognosis for recovery is usually very good with proper care. But as the name suggests, strangles can affect a horse’s respiratory system. Symptoms include:

• Fever.
• Abscesses in the mandibular lymph nodes.
• Nasal discharge that can include thick white and yellow mucus.
• Inflammation of the throat.
• Difficulty swallowing.
• Wheezing.
• Coughing.
• In rare cases, bleeding from the capillaries.

Good biosecurity practices are the best defense against the disease. The Equine Disease Communication Center’s “What is biosecurity?” offers excellent recommendations. The EDCC also recommends the following:

• When possible, isolate new horses for up to three weeks when they are being introduced to a new facility. 
• If you have handled an infected animal during an outbreak, avoid coming in contact with susceptible animals. 
• Wear protective clothing, avoid using the same equipment on multiple animals, and disinfect both your hands and equipment when moving between animals.

This “Strangles Fact Sheet” from the EDCC has more information on this disease, tips and suggestions.

Strangles reported in Whidbey Island horses, but an issue for all horse owners

Dr. Amber Itle
Assistant State Veterinarian 

Last week, strangles was diagnosed in a horse and two ponies at a Whidbey Island stable. There are a total of five horses and two ponies on the premise and the infected animals were recently purchased from a sale yard in Oregon.

While there is no formal quarantine for the facility, the owners have committed to isolating the infected horse and ponies, which are all under the supervision of a veterinarian. Additionally, no animals are currently being allowed on or off the premise.

Strangles is rarely fatal and the prognosis for recovery is usually very good with proper care. But as the name suggests, strangles can affect a horse’s respiratory system. Typically, signs of the disease include:

• Fever.
• Abscesses in the mandibular lymph nodes.
• Nasal discharge that can include thick white and yellow mucus.
• Inflammation of the throat.
• Difficulty swallowing.
• Wheezing.
• Coughing.
• In rare cases, bleeding from the capillaries.

While strangles is contagious and endemic in Washington, it is not usually fatal. Still, it is a reportable disease, meaning any diagnoses of strangles should be reported to the Washington State Veterinarian's Office.

The best protection against strangles is practicing good biosecurity. Here are some other suggestions from the Equine Disease Communication Center (EDCC):

• When possible, isolate new horses for up to three weeks when they are being introduced to a new facility. 
• During an outbreak, such as the situation at the Whidbey Island facility, avoid coming in contact with susceptible animals after handling an infected animal. 
• Wear protective clothing, avoid using the same equipment on multiple animals, and disinfect both your hands and equipment when moving between animals.

The EDCC also publishes this “Strangles Fact Sheet,” which has more tips and suggestions.

Veterinarians should alert the State Veterinarian's Office of reportable diseases by calling (360) 902-1878.