Equine Lyme Disease : Tick Tock, Tick Season Is upon Us

Ticks, horses, people and pets. The the last three are great, but what about those ticks? How could they be avoided or prevented from attaching. How to support prevention of the tick borne illnesses they cause for horses, humans and dogs? Most commonly, Lyme borreliosis or Lyme disease is among the most talked about tick borne illness. Lyme disease is characterized by symptoms caused from the spirochete bacteria Borrellia burdgorferi transmitted by the deer tick or Ixodes species.

In a horse, human or pet a tick bite area may appear hot, red, or inflamed. A horse may show symptoms of decreased activity, appear painful of lame, signs may also include kidney issues or no symptoms at all.

There are many sprays, tapes, ultrasonic devices, etc. on the market to try to prevent ticks from attaching. For horses and dogs, vaccine companies have created Lyme vaccinations. When administered at appropriate intervals animals are able to build an immune response to help in preventing an infection. There is no perfect vaccine and this is one step in prevention for this one major disease transmitted by ticks. Ticks are able to transmit other diseases such as piroplasmosis and ehrlichiosis to name a few additional diseases; preventing a tick bite is the first step.

What about an equine pre-purchase Lyme titer? In a study of Lyme titers performed in 2016, 33% are Lyme positive on the test with no clinical signs.  The best method of prevention is avoiding ticks and avoiding tick bites.

Horse “fly-sprays” often contain permethrin, many homemade recipes have proven scientifically ineffective and should be used with caution. For humans it is recommended to treat clothing, foot wear with products containing 0.5% permethrin, stronger concentrations do not have more power, rather they will last longer over time on clothing. It is a good idea to use Environmental Protection Agency (EPA) registered repellents. Check your horse and yourself for ticks frequently and showering off after being outdoors. The mane, tail and flank are common places where ticks can attach on a horse. It is a myth that ticks are only found in long grasses, rather ticks can climb onboard a horse leg, lip, tail hair by resting on a short blade of grass and grasping on with its first pair of legs outstretched.  Ticks do not discriminate as to which host they hop a ride for a good lunch, they will ride on a dog, horse or human and if the opportunity presents will transfer from one to the other and enjoy “dinner”.

To remove a tick use fine-tipped tweezers or a tick removal tool to grasp the tick as close to the skin’s surface as possible. Pull straight away from the skin, avoid twisting. Make sure the mouth parts are fully removed. Do NOT use a hot match, petroleum jelly or nail polish remover to try to remove a tick. This will cause the tick to regurgitate back into the host and can cause irritation to the skin. After removal clean area with soap and water or rubbing alcohol. After tick is removed, either stick them to sticky tape or place in a jar of rubbing alcohol. Tossing them onto the ground creates the opportunity for the tick to attach again or to another animal.

Ticks are able to survive in fairly cool conditions as well as fairly warm conditions. Heading into summer a myth is that once it is finally hot out the ticks are no longer out or once the weather cools ticks cannot survive. Ticks are amazing creatures at survival and can still grab on for a blood meal in some extreme temperatures.

Avoiding, preventing and checking for ticks is key in reducing the chances of a tick borne illness.

Lyme Disease in Horses

Ticks can transmit a number of disease-causing organisms to horses, including Lyme disease. Lyme disease is caused by the bacterium Borrelia burgdorferi. Many horses are exposed to this organism through tick bites, but few develop clinical illness, usually months post tick bite.

As in dogs and people, the possible diagnosis of Lyme disease often arises when more common causes of lameness, joint swelling, kidney disease, moon blindness or incoordination have been ruled out.

Typically, two blood samples are taken 2 to 3 weeks apart to see if anti-Borrelia antibody levels have changed significantly to indicate active infection. The two samples are important because many normal horses may carry high antibody levels. The disease can also be diagnosed by finding the organism in tissue taken by biopsy from an affected joint or lymph node. The SNAP test kits utilized for testing dogs for Lyme disease are likely valid for use in the horse, but so far are not licensed for that purpose.

If evidence of Lyme disease is found, a veterinarian may try a course of antibiotics to see if this will improve the horse’s clinical abnormalities. There are currently no Lyme vaccines approved for use in the horse.

Horse owners need to be tick-vigilant and manage their horses’ environment to reduce tick habitat. Clearing brush out of pastures and along both sides of fence lines is recommended. Keeping pastures mowed may also be helpful. Before riding through long grass or brush, use of topical insecticides is highly recommended.

Author:  Julia Wilson, DVM, MN Board of Veterinary Medicine.

This article was shared with permission from University of Minnesota Equine Extension Program. Make sure to follow them on Facebook and YouTube for even more equine information & education!

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