Lyme Disease In Horses

Submitted by Veterinary Wellness Partners on Tue, 07/01/2014 - 2:15pm

Lyme disease in Horses

You may be hearing about Lyme disease becoming more common in Ohio this season. There has been a significant increase in the population of deer ticks in Ohio since 2009. The spread of the Black Legged tick has followed a general trend from Southeast to Northwest, with most of our area affected.  This are includes Wayne County, Stark County, Summit County, Holmes County and the surrounding areas.This expansion has brought with it the risk of Lyme disease to not only your canine family members but to your equine family as well.

We would like to bring to your attention and hopefully educate you about the basics of Lyme disease as it pertains to your horse.  So what is Lyme disease?  It is a tick-borne illness named after the town in Connecticut, Old Lyme, where it was first discovered. It is caused by a bacteria, Borellia Burgdorfei. Lyme disease is most common in the Eastern United States, with alarming increase for many states.  Unfortunately, Ohio is one of the states that has seen a tremendous increase in the incidence of Lyme disease

Signs of Lyme disease in horses may be vague and intermittent in the early stages of infection. Often, Lyme disease symptoms can be mistaken for joint or muscle pain or even symptoms of equine protozoal myelitis (EPM). This is why prevention is key.  Some of the signs associated with an infected horse are:

  • -Lethargy
  • -Weight loss
  • -Persistent fever
  • -Loss of appetite
  • -Inflamed and painful joints
  • -Muscle tremors
  • -Anterior uveitis
  • -Laminitis

Lyme disease is diagnosed with a blood test to identify antibody levels in horses suspected with the disease. Unfortunately, testing for antibodies can be fairly inaccurate since it is possible for a horse to test positive (having been exposed and developing antibodies) but not yet developed the active disease. There is a newer Lyme multiplex PCR test that is sensitive to the DNA of the disease causing organisms. This test is much more accurate and Lyme disease can be detected as early as 2-4 weeks following infection.

The treatment for Lyme disease in a horse involves oral doxycycline or intravenous tetracycline. The longer that treatment is delayed, the less likely the infection can be cleared. Treatment may be required for months to resolve the infection.

How can we prevent Lyme disease in our horses? There is currently no Lyme vaccine labeled for horses. Although the canine Lyme vaccine has been used it horses, it is not approved for equine immunization and is considered off-label.  Using insect repellent is your best defense against ticks on your horses. Use products containing permethrin and cypermethrin which will serve as a repellent and also prevent them from attaching to your horse for several hours.

Another important part of tick prevention is maintaining areas of tall grass and over-growth in pastures and around barns. These areas are favorable habitats for ticks and by clearing these areas you are reducing the risk of ticks on your property. It is advised to check your horse daily during tick season. Be sure to check areas of sensitive skin.  Areas such as groin, girth, along the legs and under mane and tail area all places ticks are likely to be found.

If you do find an attached tick, removing it as soon as possible will help lessen the chance of disease transmission. Always take precaution when removing and handling a tick. You should wear gloves to avoid getting blood from the tick on your skin. Grasp the tick at the base of the head, as close to the horse’s skin as possible. Slowly pull the tick out without squeezing the main body. Removing the tick too quickly can leave parts of the tick embedded in the horse’s skin.


This Article was composed by Samantha Wenger, R.V.T.

Edited and published by Dr Fink on behalf of Orrville Veterinary Clinic, Inc.