Lyme Disease in Horses – Essential Facts Explained!

Last Updated on January 18, 2023

In recent years there is an increasing level of awareness around the risks of Lyme disease to humans, but is Lyme disease in horses also a big problem?

Unfortunately, horses can also contract Lyme disease, and this condition can be difficult to diagnose and treat. The symptoms of Lyme disease in horses can be subtle and very variable, leading to the condition going undetected for some time.

When left untreated, Lyme disease can have detrimental effects on the long-term health of your horse. The cost of treating Lyme disease in horses can also become quite high, as the period of treatment is often prolonged and extensive.

The key to a prompt diagnosis and treatment of Lyme disease in horses is to learn to recognize the risk factors and warning signs of this disease. So, to help you figure out if your horse may have Lyme disease, we’ve got everything you need to know right here!

What Is Lyme Disease In Horses?

The key to a rapid recovery from Lyme disease is a prompt diagnosis – the sooner the disease is identified and treatment is started, the shorter the recovery period will be. Any delay in diagnosis and treatment can reduce the chances of your horse making a full recovery.

Therefore, familiarizing yourself with the most common symptoms of Lyme disease in horses is the first step to combating this debilitating disease. But what exactly is Lyme disease, and how do horses get this disease?

Lyme disease is a tick-borne illness that can affect both humans and horses. The correct medical name for the condition is Lyme Borreliosis because the causative agent is a spirochete bacteria called Borrelia burgdorferi.

When a tick attaches to a horse or human, it bites the skin and secures itself in place using its strong mouthpiece. The bacteria are then passed from the tick into the bloodstream of the human or horse it has bitten.

Lyme disease in horses is most common in areas where ticks are increasingly prevalent, especially in the warmer months. Tick populations tend to be higher in areas with higher densities of animals such as deer and sheep. They prefer longer grass and brush, so populations will be higher in overgrown pasture land.

What Are The Symptoms Of Lyme Disease In Horses?

In recent years, we have become much more knowledgeable about the symptoms of Lyme disease in humans, and many of us are aware to check for a bullseye-shaped rash after being bitten by a tick. However, Lyme disease can be much harder to detect in horses and other animals.

The key to a full and fast recovery from Lyme disease in horses is a prompt diagnosis, enabling treatment to be initiated as soon as possible. Familiarizing yourself with the common symptoms of Lyme disease in horses will help you to recognize when your horse might have contracted this disease.

The important thing to remember about Lyme disease in horses is that not all horses will show all symptoms. The signs of Lyme disease in horses can be variable and very subtle – it may be that you feel that your horse is off-color and not quite right, but can’t figure out a reason why. This is particularly the case in the early stages of the disease, and in the latter stages, some of the symptoms of Lyme disease in horses become much more obvious.

Here are some of the most common symptoms of Lyme disease in horses to look out for:

  • 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. You may feel that your horse is not as keen to exercise as normal, or that it seems to spend more time standing still in the paddock. The general demeanor of your horse may also change, with a normally good-natured horse becoming grumpy and irritable.

  • Fever

Tick bites can often lead to a low-grade “tick fever” that tends to be of little consequence. However, horses that contract Lyme disease will often develop a high fever within the first three days after being bitten.

  • Reduced appetite

Any reduction in your horse’s appetite following a tick bite should be a cause for concern. Most horses have a healthy, consistent appetite, and any changes in eating habits may be an indication of a medical problem such as Lyme disease. So, if your horse stops eating or you notice a gradual weight loss, it is a good idea to seek veterinary advice.


  • Lameness

Lameness is the term used to describe a disruption in a horse’s normal gait, and it often signifies pain occurring in the horse’s skeletal or muscular structures.  Lyme disease can cause a horse to be lame but this can be a tricky symptom to identify, as it can often appear and subside on an irregular basis. Lameness that is not localized or that shifts from leg to the leg can be an indicator of Lyme disease in horses

  • Swollen joints

The reason that the lameness caused by Lyme disease in horses is so variable is that this condition can cause inflammation and swell in the joints. Any swelling symptoms in equine extremities should always be paid special attention to as it can signify several causes including injury and disease.  A horse looking “stocked up” in their joints may be suffering from Lyme disease.

  • Tender or sore skin and muscles

Another very subtle symptom of Lyme disease in horses is the tenderness of the skin and muscles. The horse will struggle to communicate this pain to you, so look out for signs such as discomfort when grooming or saddling.

  • Long-term symptoms in chronic cases of Lyme disease in horses

As this condition progresses, the symptoms become more obvious and severe. This is because the disease progressively attacks the nervous system, causing a range of different neurological symptoms.

According to the Cornell College of Veterinary Medicine, horses with untreated, long-term Lyme disease may have difficulty eating or swallowing, caused by nerve damage to the affected areas. Inflammation in the brain, also known as encephalitis, can cause other neurological symptoms such as a head tilt.

Can You Ride A Horse With Lymes Disease?

Whether a horse with Lyme disease can be ridden will depend on the severity of the disease and the symptoms the horse is displaying. Remember that the signs of Lyme disease in horses can be very subtle, and your horse may be feeling unwell even if you cannot spot anything wrong!

If your horse shows any of the symptoms listed above and has been diagnosed with Lyme disease, it should not be ridden. The most common but hard-to-recognize sign of Lyme disease in horses is lethargy, and your horse needs plenty of rest to make a full recovery.

So, when it is OK to start riding your horse again following the diagnosis and treatment of Lyme disease? This will need to be decided on a case-by-case basis, as only you will know when your horse is completely back to normal. If the horse is no longer showing any symptoms of Lyme disease and seems to have normal energy levels, it is probably OK to start gentle exercise again.

Remember that a horse with Lyme disease will have normally had a long period off work, and will need to start from scratch when it comes to a fitness program. Monitor your horse’s energy levels and willingness to work, and adapt your work accordingly.

Should I Buy A Horse With Lyme Disease?

Buying a horse with any disease or disorder is a risky business, and caution should be taken when buying a horse with Lyme disease. It is advisable to get a full and independent assessment of the condition of the horse by a veterinarian before agreeing to purchase the horse. You should also bear in mind that not all horses with Lyme disease make a full recovery and that the treatment period can be prolonged and expensive. 

Is Late-Stage Lyme Disease Fatal In Horses?

The good news is that Lyme disease in horses is rarely fatal, but it can cause long-term debilitating symptoms that never fully resolve. The faster this condition is diagnosed and treated, the lower the risks of the horse suffering from lifelong side effects.

In horses that enter late-stage Lyme disease without any treatment, it is common to see chronic weight loss and persistent lameness caused by swollen joints. Neurological symptoms such as a head tilt and difficulty swallowing can also persist, even after treatment for the condition has been initiated.

How Is Lyme Disease In Horses Diagnosed?

Before Lyme disease in horses can be treated, a definitive diagnosis must be reached. If you identify some or all of the above symptoms in your horse, you should contact your veterinarian for advice.  They will carry out a full physical examination and take some preliminary screening tests to rule out other causes before testing for Lyme disease.

One of the issues with Lyme disease in horses is that the initial tests can be inconclusive. Tests can often come back negative within the first few weeks of exposure. When this happens, your veterinarian may wish to retest your horse or pony, particularly in situations where the symptoms persist and no other causes can be determined.

There are two main tests for Lyme disease in horses, and your veterinarian will most likely carry out both tests. The first is a simple SNAP test which can be done at the veterinary clinic – this tests the blood of the horse for the presence of antibodies to the bacteria that causes Lyme disease in horses. However, this test is not all that accurate, which is why the second test is also required.

The second test for Lyme disease in horses is carried out at Cornell University and gives a much more accurate assessment of the type of antibodies present and the likelihood of an active Lyme disease infection. It can help the veterinarian to assess whether a positive result is due to an active infection, or a false positive due to a previous infection or vaccination against Lyme disease.


How Is Lyme Disease In Horses Treated?

If 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 be kept at bay.  Most veterinarians will prescribe either intravenous or oral antibiotics to combat the bacteria transmitted by infected ticks.

Here are some of the most common treatment options for Lyme disease in horses:

  • Antibiotics

Your veterinarian may prescribe a course of oral antibiotics, such as doxycycline or ceftiofur. These come as a powder to be administered in food, or a paste to be squirted directly into your horse’s mouth. Other antibiotics such as tetracycline need to be given by intravenous injection, and can only be administered by a veterinary professional.

Whichever antibiotic is prescribed, it is normal for the horse to need a prolonged course of medication for several weeks. This makes the cost of intravenous antibiotics very high, as you will need to pay additional fees for your veterinarian to administer the drug every day. It may be cheaper for the horse to be hospitalized for treatment rather than pay for a vet visit fee every day.

  • Pain relief

Banamine is a common anti-inflammatory and pain reliever that some vets may prescribe in conjunction with antibiotics.  Banamine will not treat the underlying cause of Lyme Disease but will ease some of the discomfort shown by the horse like muscle soreness or swelling in the joints.

  • Nursing care

In severe cases of Lyme disease in horses, it may be necessary for the horse to be hospitalized to receive intensive veterinary treatment and nursing care. This may include assisted feeding and intravenous fluids to keep the horse hydrated.

How To Prevent Lyme Disease In Horses

As with all equine diseases, prevention is better than cure! There are many steps you can take to reduce the risk of your horse contracting Lyme disease. So, if you live in an area that is at high risk for Lyme disease in horses, take a look at some of the following suggestions:

  • Maintain grazing land

Ticks rely on longer grasses and brush to be able to access their host animals. If the grass is kept relatively short, it is much harder for the tick to make its way onto your horse.

The high-risk periods for ticks are the warmer months – late spring through to early fall. During these periods, keep your pasture land well maintained, regularly mowing any overgrown areas. If this task seems very daunting due to the size of your paddock, consider reducing the area your horse grazes to keep it more manageable.

  • Grooming

The problem with ticks is that they are very difficult to spot, and can go undetected for days or even weeks after they have attached to your horse! A consistent, regular, and thorough grooming routine will make it easier to spot ticks, and also help to dislodge any that have not yet attached to the horse’s skin. Pay attention to high-risk areas such as under the belly and on the chest.

  • Fly repellents and insecticides

Use horse-friendly insect repellents that contain permethrin (like Absorbine’s Ultra-Shield Ex Spray) to repel ticks and other insects. If you find a tick attached to your horse, speak to your veterinarian about the best way to remove it.

Lyme Disease Treatment in Horses


Conclusion – Lyme Disease In Horses

So, as we have learned, Lyme disease in horses is a debilitating condition that can cause long-term problems if left untreated. Early intervention is key in avoiding the more serious and sometimes irreversible effects of Lyme disease, such as neurological deterioration and chronic weight loss. In warmer areas, tick populations are on the rise, and it is important to reduce tick habitats and groom your horse regularly to reduce the risk of Lyme disease.

We would love to hear your thoughts on Lyme disease in horses! Have you ever owned a horse that was diagnosed with this condition? Or perhaps you’ve got some questions about the diagnosis and treatment of Lyme disease in horses? Leave a comment below and we will get back to you!


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 horses 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.
The antibiotics Doxycycline and Amoxicillin are often prescribed to help control symptoms of Lyme disease in horses. The chances of a full recovery from Lyme disease are greatly increased if the condition is diagnosed and treated as soon as possible after infection.

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

The cost of treatment for Lyme disease in horses will depend on various factors. These include the type of diagnostic tests, the severity of infection, the type of treatment, the location of the patient, and if hospitalization and supportive veterinary care are necessary.
Symptoms of Lyme disease are not always obvious, which means a 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 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 is the most common tick-borne disease.