Ubiquitous news reports of Lyme disease and its affects on humans warn of dire consequences for those who ignore the bite of an insect the size of a pencil tip. Dr. Bonnie Barr, VMD, DACVIM, of Rood & Riddle Equine Hospital, says the tiny insect can also have a weighty effect on our 1,000-pound equine friends.
In a Veterinary Answers Q&A with OffTrackThorouhgbreds.com, Dr. Barr offers her perspective on the disease, providing tips for prevention, and suggestions on where to look for a tick that may be nestled into a horse’s hair.
The 1997 graduate of the University of Pennsylvania, who received her Diplomate American College of Veterinary Internal Medicine in 2003, says that while it is not known whether there is an uptick in the number of cases of Lyme in horses, or simply more accurate testing, Lyme disease is a disease that should be considered when an equine shows vague signs and symptoms of the illness.
Q: Lyme disease stories have been all over the news, as occurrences in humans reportedly soars. Is there evidence that more horses are testing positive for the disease as well? Does it appear that Lyme disease is on the rise in horses, and if so, what could be causing the uptick?
I am not sure if more horses are testing positive for Lyme disease or if the disease is on the rise in horses. Recent improvements in diagnostic testing for Lyme disease has enabled veterinarians to better define the infection status of the horse, specifically if early or chronically infected. The test also distinguishes between an antibody increase due to infection and vaccination.
The test is called Lyme Disease Multiplex Testing for horses and it is performed at Cornell University.
Q: Which circumstances put a horse more at risk for contracting the disease? For example, are horses who graze in tall grass more prone than those with mowed paddocks?
Risks include: tall grass, areas with a lot of leaf or brush piled in yards, paddocks or on the farm, pastures boarded by brush thickets or forests
Q: What preventative tools are available to owners, and is there a vaccine? And how effective are these tools?
Preventative tools: 1. Minimize the tick population-keeping the fence lines mowed, grass trimmed short around barns/arenas, move horses to pastures not boarded by bushy areas or forests
2. Check horses for ticks daily-pay particular attention to the base of mane, neck, under the tail and in the ears
3. Apply insect repellant or wipes that contain Permethrin or Pyrethrin
4. Monitor for any vague symptoms-lethargy, depression, low-grade fever
5. Remove any tick seen within 24 hours
Currently there is no commercially approved vaccine for horses. Some have used the commercially available vaccine for dogs.
Q: If an owner pulls a tick off a horse, should the site be monitored, and if so, what types of reactions to the skin should the owner look for?
Due to the type of hair coat a horse has, the characteristic bulls-eye-type lesions might not be seen. There is a possibility of a reaction in areas of less hair coverage, so a rash with a bulls-eye or raised appearance may be noted.
Q: Even if no tick is present, are there telltale signs that an owner can spot, which indicate the presence of the disease?
The clinical signs are vague and similar to other disorders. Some symptoms are lethargy, low-grade fever, sporadic lameness, shifting leg lameness, weight loss, altered mentation, swollen joints, neck/back pain, changes in behavior and neurologic signs.
Q: Once a veterinarian confirms the disease, what course of treatment is used to cure it, and what is the duration of treatment?
Treatment is antibiotics, specifically tetracyclines. These include Oxytetracycline, Doxycycline, and Minocycline. Usually, a treatment course is 30 to 45 days.
Q: Lyme disease in people can have a profound impact on health. Is it the same in horses?
Lyme disease can be debilitating and chronic. Long-term complications can include damage to joints, skin, nervous system or even vision.
6 responses to “Rood & Riddle Q&A on Equine Lyme disease”
After researching Lyme disease, I insisted that my vet test my horse using Cornell University’s test and when she came up with a slight positive on Osp A antigen my vet said that they considered her negative since the Osp C and Osp F were negative. I wasn’t convinced and got a second opinion from a vet who said we should retest. A month later her numbers had sky rocketed and she was definitely positive for Lyme disease. We started treatment immediately. One week of intravenous Oxytetracycline, then a month or more of Doxycycline orally. In the last month before we started treatment she developed a horrible hoof abscess, a fungal skin condition, hives, and pressure sores from lying down so much. I feel that all of these conditions are related to having her immune system compromised by the Lyme disease. I hope that the treatment is successful and I plan to test annually for Lyme disease in both of my horses from now on. If you are in an area where Lyme disease is present, please consider testing regularly, it may save your horses life. The symptoms can be vague and non-specific. But the consequences can be devastating. Cornell University’s test is the best out there, I highly recommend it. Keep in mind that results can change dramatically in just a month, so if there is any doubt, retest.
I attended an herbal medicine course two weeks ago sponsored by CNHP, certified natural health professionals. Teasel root tincture has been giving to humans successfully to treat Lyme (off the grid, of course) which is difficult to diagnose given the transient nature of the antibodies. can Teasel root tincture be used for horses?
Thanks so much for writing this article!I found it when I googled Lyme Disease. Goffin’s blood test just came back positive! It explains all of the weird symptoms he has been having! He starts treatment tomorrow! Thanks again for writing this!
Is it possible to clinically differentiate between a false neg for EPM & Lyme’s?
This is a true cautionary tale. Lyme is real and it can be serious. Don’t let your healthcare providers or veterinarians tell you “it isn’t around here.”
In 2007, I was diagnosed with Lyme disease after insisting that I be tested for it, even though WV had reported only a handful of cases in previous years. I was treated with antibiotics. Symptoms (particularly fatigue and joint pain) lingered for several years.
What I did not know was that three dogs and two of my horses had also contracted the illness.
My oldest dog suffered severe joint pain, loss of energy, and eventually kidney failure and was euthanized in 2010.
In her first year off the track, my beautiful OTTB mare glowed with good health despite battling multiple abscesses. But then she just seemed to fail to thrive. No more abscesses, but began exhibiting weight loss, dull coat and just a general malaise. Since she wasn’t in work, just a pasture puff due to a knee fracture, it was hard to tell if she was depressed. Two weeks after my sweet dog crossed the bridge, the stable owner came out to feed the horses breakfast and found my girl dead in the run-in with no injuries, no signs of struggle or wind-milling. It appeared she had just dropped.
Not long afterward, my daughter called to tell me her dog (brother to my remaining dog) tested positive for Lyme. I had my dog tested, and got the same results. So the calm, quiet demeanor of my puppy may not have been totally based on his good nature. He, too, was successfully treated with antibiotics.
At this point, I still had not connected the Lyme dots. (And I feel like such a fool for not having the horses tested.)Six months later, an almost identical situation presented itself and my round, dappled bay gelding was found in the pasture the next morning. When I fed him the night before I snapped some photos of his gorgeous dapples. Then he was gone!
I was not in a position financially to have necropsies performed, but I feel strongly there was link to Lyme disease in my pets’ deaths.
In no case did any of us display an obvious bulls-eye reaction to the tick bite. As in humans, Lyme in dogs and horses may mimic other diseases or conditions. My dogs are all now tested annually for Lyme.
If you have the least suspicion that you or your animal have been exposed to Lyme, invest in the test. Insist on it!
Thank you so much for this letter! I was talking with someone today who was newly diagnosed with Lyme, and listening to her describe the symptoms made me wonder why medical doctors would be so hesitant to do a test if a human patient has even the slightest concern, and especially people who spend time in barns, and out riding.
I am also very sorry about your horses. What a tragic result.