Most Common Symptoms of Lyme Disease in Horses

Last Updated on December 8, 2021 by Urska

Is there Lyme disease in horses? The first horse I was invited to help train and show on was a gorgeous grey thoroughbred was named Teddy.  Teddy had tons of potential and was athletic and willing, just a little green around the edges.  

Teddy began redeveloping from his lameness during my first year of working with him. Strangely, he sometimes would lag behind me at the end of a 10-foot lead rope when I brought him in from the field.  

As a 17-year-old just getting started in the business, I had no idea. These were troubling symptoms of an all too common disease for equines: Lyme Disease.  

Symptoms of Lyme Disease in horses can often disguise themselves as other common problems. When left untreated, it can have detrimental effects on the long term health of your horse.

What is Lyme Disease in Horses?

Thus, familiarizing yourself with the most common of symptoms, is the first step to combating this debilitating disease.

Lyme Disease is a tick-borne illness that can affect anything from humans to horses. 

 It is caused by a bacterium that is carried most commonly by deer ticks and transmitted through tick bites.  Lyme Disease is most common in the North East, where ticks are increasingly prevalent, especially in the warmer months.

Unlike in humans where Lyme can be detected by a bullseye shaped rash following contact with a tick, Lyme Disease can be much harder to detect in horses and other animals.

Lyme Disease Symptoms in Horses

Lyme Disease can be very subtle in most animals, and this is no different for horses.  However, familiarizing yourself with the common symptoms will help you know when to consider Lyme Disease as a culprit.

  • Low energy or irritability: Lyme Disease can often present itself in horses as a kind of depression, which can be easily mistaken for other ailments.  
  • Fever: Tick bites can often lead to low-grade “Tick Fevers” that are eventually of little consequence. However, equines that do contract Lyme Disease will often present themselves in the horse with a high fever within the first three days.
  • Loss of Appetite: Most horses maintain a healthy, consistent appetite unless suffering from some kind of distress.  The same goes for horses suffering from Lyme, as they will often show a decrease in appetite. If this should prolong, then chances are that your horse must have contracted Lyme disease.


  • Lameness: Lameness is characterized as a disruption in a horse’s normal gait, and often a signifier of pain occurring in the horse’s skeletal or muscular structures.  Lyme Disease also can cause a horse to be unsound but can be a tricky symptom to track, as it can often appear and subside on an irregular basis. Lameness that is not localized and oases ftican jump from leg to leg is an indicator of Lyme Disease in horses

More Signs and Symptoms

  • Swelling in Joints: Any swelling symptoms in equine extremities should always be paid special attention to as it can signify a number of causes including injury and disease.  A horse looking “stocked up” in their joints may be suffering from Lyme.
  • Tender or Sore Skin and Muscles: A horse that is continually weak over a period of time, especially without having been through a rigorous session of work or having possibly done something during turnout, could possibly be infected by Lyme. Thus, always lookout for a horse that appears uncomfortable during grooming or saddling.
  • Serious Symptoms in Chronic Cases:  According to the Cornell College of Veterinary Medicine, horses with untreated, long-term Lyme Disease may have the following symptoms, suggesting the nervous system has been compromised:
    • Dysphagia, or difficulty swallowing
    •  Head Tilt
    • Encephalitis, or inflammation in the brain

Lyme Disease Treatment in Horses

When left untreated, Lyme Disease can cause havoc on a horse’s whole body health. However, when caught and treated early enough, its detrimental effects will now be kept at bay.  Most veterinarians will prescribe either IV or Oral antibiotics to combat the bacteria transmitted by infected ticks. 

  • Testing: If you recognize many of the above symptoms, you should contact your vet.  They will likely do a few preliminary screenings to rule out other causes before testing for Lyme.  Tests can come back negative within the first few weeks of exposure, and when that happens, it will be mandatory for you to retest your horse or pony, in case any symptoms persist and no other causes can be determined.   


Treatment and Medicines

  • IV or Oral?: Vet care can be extraordinarily costly, and in most cases, there are multiple routes one can consider when treating Lyme Disease both with their own advantages and disadvantages
    • IV Antibiotics tend to be more effective when administered in the case of Lyme Disease. But, they can also lead to higher treatment costs.  Thus, those whose concern is on relapse or with horses that have already suffered a relapse should consider IV medication.
    • Oral Antibiotics can be slightly less effective when compared to their intravenous counterparts. However, they require less monitoring by the veterinarian and can, therefore, be less costly. Thus, in cases where Lyme seems to have been caught in its early stages, Oral Antibiotics would be a very viable and effective treatment plan.


As exposure to disease is often very highly correlated with environment, there are many steps you can take to keep your horse’s risk level low.

  • Maintain Turnout Areas: If your horse feeds regularly on ticks grassy and wooded areas, you should make sure the pastures are well maintained.  Also, mowing and weeding are essential to keeping tick exposure low as well as keeping low shrubbery in pastures to a minimum.  
  • Keep A Consistent Grooming Schedule: Ticks often love to hide in horse’s nice thick coats and can sometimes be difficult to see from a distance.  But, consistently grooming your horse and making sure you do a thorough grooming at least once a week, will help make it easier to spot ticks before they are able to sink their teeth in.  This is particularly important for those horse owners or caretakers who do not clip their horses or those who look after equines with naturally thicker body hair or feathering above the hooves. 
  • Fly Spray: Use a horse-friendly insect repellents that contain permethrin (like Absorbine’s Ultra-Shield Ex Spray) to repel the multitude of insects that will mostly come its way, especially Lyme carrying ticks

Lyme Disease Treatment in Horses



Contact with ticks is not a cause for immediate alarm and a panicked call to the vet. Keeping these symptoms in mind can lead to early intervention in the case of Lyme Disease.  

Early intervention is key in avoiding the more serious and sometimes irreversible effects of Lyme. These effects are neurological deterioration and vision problems. 

Those in the North East are statistically more likely to encounter Lyme Disease in horses. The tick population is on the rise. Horse owners and lovers should take note of the most common symptoms of Lyme Disease. Do your best in taking care of the health of your horses and ponies.  


Is Lyme disease curable in horses?

Lyme disease is a tick-borne illness. It is caused by an infection with Borrelia burgdorferi bacteria, which is transmitted to people through the bite of infected ticks. Borrelia burgdorferi can cause symptoms such as fever, weight loss, fatigue, stiffness of the neck and joints, lameness and swollen lymph nodes. Lyme disease can affect both humans and animals.
In humans, the disease can be cured if it's caught early enough. However, this may not be the case for horses as the symptoms are not as obvious. It can be difficult to diagnose due to its similarities with other diseases and its lack of symptoms in the early stages.
Lyme disease in horses cannot be cured but treatment usually helps control the symptoms.
The antibiotics Doxycycline and Amoxicillin are often prescribed to help control symptoms of Lyme disease in horses.
There is no vaccine for Lyme disease and early detection and treatment is critical.

How much does it cost to treat a horse for Lyme disease?

Lyme disease is a relatively big problem for horses. The cost for treatment usually depends on the type of diagnosis, severity of infection, type of treatment, location, and if veterinary care is necessary for anything outside of administering antibiotics.
Symptoms of Lyme disease are not always obvious, which means diagnosis can be difficult. However, if the horse shows common symptoms of Lyme disease - fever, lethargy, swollen joints or pain - their vet should be able to diagnose them quickly and recommend treatment.
The cost of treatment ranges from around $400-$500 per horse, with antibiotics costing about $20-$40 each at retail prices. Veterinary care also has an associated cost that ranges from about $100-$300 per horse depending on how many treatments are needed and their severity.

How do they test for Lyme disease in horses?

A blood test is the most commonly used for diagnosing Lyme disease in horses. The test checks for antibodies, which are produced by the horse’s immune system when it tries to fight off the Lyme disease bacteria.
The tests can be done by drawing blood from the animal and testing for antibodies against the Borrelia burgdorferi, the bacteria that causes Lyme disease. If it is positive, then the horse will need to be treated with antibiotics to prevent complications such as kidney damage.
A blood test, also known as an ELISA (enzyme-linked immunosorbent assay) or IFA (indirect fluorescent antibody), can determine if an animal has been exposed to Borrelia burgdoferi but it typically it takes about 4-6 weeks for an animal to develop the antibodies necessary to be detected by the test.

How common is Lyme disease in horses?

Lyme disease in horses is rare. In the US, only about 1% of the horses have been diagnosed with Lyme disease. Although cases have been on the rise in recent years and it is becoming more common for horses to contract Lyme disease, it is still relatively rare and accounts for less than 1% of all equine diseases and conditions.
Ticks can be infected with more than one pathogen, and the same tick bite can transmit more than one type of pathogen. In fact, a single tick bite can transmit as many as three different pathogens to a person. Lyme disease is transmitted through a deer tick bite and it's the most common tick-borne disease.