Mythbuster Monday: Can Lyme Disease Be Cured?

On Mythbuster Monday, we tackle a variety of equestrian myths to either bust or confirm. Today’s discussion: Are horses that are treated for a positive Lyme test cured once they receive treatment?

It’s Mythbuster Monday, where Horse Nation dives into different equestrian myths and provides research-based evidence to either bust or confirm those myths. Today’s topic:  Curing Lyme disease. Are horses who are treated for a positive Lyme test cured once they receive treatment? What types of medications are used? Will horses have flare ups later in life? How does the virus present itself? Read further to find out!

Myth: Lyme disease can be cured. 

Myth or Fact: Myth


Lyme disease is tick-borne infection that can affect many different species, including humans and horses. When a tick latches on to the horse and begins to feed, it transmits the infection through the blood. In order for the horse to be infected, the tick needs to be attached to the horse for at least 18 hours. Exposure to Lyme disease in horses is especially high because they come in contact with ticks regularly.

Clinical signs of Lyme disease include swollen lymph nodes near the site of the bite, dermatitis, stiffness, multiple limb lameness, inflammation of the joints, and occasionally meningitis. Some may also notice behavioral changes, muscle wasting, weight loss, facial paralysis, coordination issues, and inflammation of the eye tissues. The most common signs include high fever, depression, leg edema, jaundice, and low white blood cell counts.

But, can you cure a horse of Lyme disease with treatment?


According to an article published by Cornell University (which accompanied a seminar presented on Oct. 13, 2020 by Dr. Thomas Divers), horses may take months to diagnose because they don’t show signs and symptoms as early as humans. While keeping horses on doxycycline or minocycline for three to four months will give what is considered a negative Lyme level when retested, the virus actually just goes dormant in the horse’s system.

In horses with the neurological signs and symptoms, prognosis is poor. Horses may go back to normal; however, relapse usually occurs with identical clinical signs as the previous time and treatment may not be effective. Dr. Divers states that the key to treating chronic Lyme flare-ups is to work towards better prevention methods.


The American Quarter Horse Association (AQHA) also published an article discussing Lyme disease. They write that many horses that are positive for Lyme disease never show clinical signs. When a horse is confirmed to have Lyme, most forms are treatable, but they’re not curable. While catching the disease early may prevent relapse, the body builds up antibodies and may become symptomatic again in the long term.


Rutgers University New Jersey Agricultural Experiment Station discuss in their article that horses are treated for their symptoms and not to cure the disease. They also write that treatment for horses is based on human treatments and trials for horses — there is no confirmed treatment for horses. Based on clinical trials, the recommendation is a month-long course of intravenous tetracycline or oxytetracycline. Even with this treatment, in contrast to humans, horses remain seropositive for years after treatment.


After diving into the research, it’s important to note that horses that test positive for Lyme disease remain seropositive for years, even after treatment. Although they may not show signs and symptoms for long periods of time, flare-ups may occur later in life. To minimize the probability of flare-ups, treating a positive Lyme disease horse early is important.

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