Talk about opportunistic: The tiny tick is highly adaptable and focused on survival.

Although often wrongly identified as insects, ticks are actually eight-legged parasitic arachnids, making them relatives of the spider.

Unfortunately, ticks can transmit a variety of harmful pathogens, including Borrelia burgdorferi, the infective organism that causes Lyme disease in humans, dogs, and horses.

The disease takes its name from Lyme, Ct., where it was first identified in the U.S. in the mid-1970s.

Lyme disease is transmitted by Ixodes scapularis (the eastern black-legged tick), found in the north and eastern part of the U.S., and Ixodes pacificus (the western black-legged tick), found in the Pacific Coast states of the western U.S. Both are also referred to as “deer ticks,” as deer are common hosts.

Ticks have four life stages: egg, larvae, nymph, and adult. From larvae stage onward, blood meals are needed to survive.

It is through feeding that ticks become infected with disease-causing pathogens. For example, the black-legged tick can become a carrier of B. burgdorferi after feeding on a white-footed mouse, which is known to carry the bacterium. If that tick then feeds on a horse, human or dog, it can transmit B. burgdorferi.

Shaped like tiny corkscrews known as spirochetes, this bacterium can colonize in the bloodstream, brain, joints, organs, and central nervous system.

At Cornell University College of Veterinary Medicine in Ithaca, N.Y., Thomas J. Divers, DVM, has devoted years of research to studying bacterial tick-borne infections in horses.

Divers notes that the rise in tick numbers and their expanding geographic range has no doubt increased the exposure of humans, horses and dogs to B. burgdorferi.

Clinical Signs of Lyme Disease in Horses

Lyme disease is the most common of several tick-borne diseases affecting horses. Diagnosing Lyme, however, is not straightforward, and can in fact be extremely challenging.

In humans, Lyme disease can affect the entire body with an array of troubling symptoms, often causing misdiagnosis. A similar problem is found in the equine world, as the clinical signs of equine Lyme disease can mimic other diseases.

Another difficulty with diagnosing Lyme in horses is that the clinical signs aren’t consistent. These signs may include:

◆ Nodular skin disease at the tick bite site

◆ Neurologic disease affecting the spinal cord, brainstem or brain

◆ Uveitis (inflammation within the eye)

◆ Overall tenderness/sensitivity

◆ Vague lameness

◆ Neck and back stiffness with pain

◆ Muscle atrophy

◆ Behavioral changes

◆ Weight loss

◆ Ataxia (lack of voluntary coordination)

Adding to the challenge of diagnosis is that clinical signs may not appear for weeks—if not much later—and the horse may only exhibit random signs.

Diagnosing Lyme

In areas of the U.S. where B. burgdorferi exposure is common, 20 to 50 percent of adult horses have likely been exposed.

“The infection rate in horses is high, but clinical disease following infection appears to be very low in horses,” says Divers.

Exposure does not prove Lyme infection, so if your horse is exhibiting clinical signs related to the disease, your veterinarian should conduct a thorough exam to rule out any other causes.

If your veterinarian suspects Lyme, blood is drawn for serologic testing to determine if the horse’s immune system has produced antibodies to B. burgdorferi.

Having a high antibody suggests the horse has been exposed to the bacteria, but doesn’t necessarily confirm the horse has Lyme disease, since numerous equine diseases share similar clinical signs.

“It’s important to remember that most horses exposed to the bacteria and having a positive antibody test show no signs of Lyme disease,” says Divers. “If the antibody remains high without a drop in titer after several months, this suggests chronic infection, but most horses with this laboratory finding appear completely normal.

“I still believe clinical Lyme disease is much less common in horses than humans,” he adds. “There might be a slight increase in confirmed equine Lyme cases, but some of this is likely due to increased diagnostics, rather than a true increase in the disease.”

Treatment

Veterinarians admit that there is no “ideal” treatment protocol for equine Lyme disease.

Drug protocol and the duration of treatment should be determined by the attending veterinarian based on where the infection is in the horse’s body.

Divers emphasizes that it isn’t appropriate to use antibiotics to treat a horse that is antibody positive but doesn’t have a confirmed Lyme diagnosis, as this can contribute to widespread antimicrobial resistance.

Drugs in the tetracycline family, including doxycycline and minocycline, have been used to treat the disease. For a horse that truly has Lyme disease, a course of antibiotics may result in improvement of clinical signs within a few days. However, completely eliminating the B. burgdorferi organisms likely requires long-term treatment of weeks to months.

Divers generally recommends rechecking the antibody levels after six weeks. If no decline in titer is visible, the veterinarian should reassess the treatment protocol.

“Recovery from neurologic disease and uveitis is difficult,” cautions Divers, adding that prognosis is guarded in horses with such clinical signs from Lyme disease.

Protecting Horses from Exposure

No vaccines for Lyme disease are currently labeled for use in horses, although a vaccine is available for dogs. Some horse owners in areas where Lyme disease is prevalent have tried using these canine vaccines, but veterinarians may be hesitant to recommend such off-label use.

The best way to protect horses from possible infection is by limiting their exposure to ticks, which typically occurs when horses are turned out in or ridden through wooded areas.

When not on a host, ticks prefer shaded, sheltered areas with vegetation. If it’s not possible to keep horses out of wooded areas completely, maintain a 10-foot mowed boundary strip between wooded areas and open pasture. Keep that strip mowed very short, since ticks usually avoid open, sunny areas with little cover.

You should also protect your horse by:

◆ Keeping pastures well mowed; don’t let them get overgrown

◆ Removing weeds/leaf litter around barns, fence lines and under trees

◆ Practicing rodent control in and around barn

◆ Applying repellent products specifically labeled for use against ticks and, ideally, approved for use on horses

◆ Checking horses thoroughly after any exposure to areas that may harbor ticks

Unless you see a tick moving on a light-colored horse, you aren’t usually aware of their presence without careful observation. Check closely in thin-skinned areas of the horse’s body, including the chest, neck, flank, under the mane and tail, inside ears, and under the belly.

It’s often said that a tick must be attached for 24 hours before the Lyme disease organism can be transmitted, but this is not black and white. The best protection plan to is keep ticks off horses as much as possible.

Even if they don’t transmit disease, the ticks can cause inflammation, swelling and itching at the bite site.

After removing a tick, clean the site thoroughly with an antiseptic made for equine use, then wash your hands thoroughly with soap and water.

The post Lyme Disease in Horses appeared first on Horse Illustrated Magazine.

After countless doctor visits and years of pain and fear of the unknown, Ableidinger finally had an answer for what was wrong: Lyme disease. Although she now knew what was ailing her, the battle was far from over as she and her husband, Scott, struggled to find a treatment that worked.

“The pain in my joints and muscles was so excruciating that I lost the ability to move my body,” she says. “I couldn’t walk, feed myself, or even do something as simple as tie my shoes.”

Eventually, they found a treatment that worked for her. Two years later, she was able to move with less pain. As she realized she may be able to get some of her life back, one thought drove her: to get back in the saddle.

Finding New Purpose

Ableidinger, who was forced to retire from owning and operating a hair salon due to Lyme, looked for a new purpose for her life. And then she thought of 4-H.

“I grew up with 4-H,” she says. “While I was very active in both the 4-H Dog and Poultry Projects during my high school years, the Horse Project was too expensive. We had the horses, but we didn’t have a horse trailer, the money for lessons, or the expensive tack that was needed to participate in shows and events.”

Fueled by a lifelong love of horses, she and her husband decided this could be it—her new purpose. In 2017, a club leader in her area of Clark County in Washington state was retiring, and someone needed to take over the 4-H Horse Project.

“I saw it as my chance to give youth the opportunity that I never had,” Ableidinger says. With that, the Ravenna Riders were born.

Covering All Needs

But this isn’t just any 4-H club. The Ableidingers want to make it more affordable for kids to have an amazing experience of working with horses. They do this by providing most of the horses, tack and equipment out of their own pocket. 4-Hers pay a small monthly fee to help with feed if they use one of the Ableidingers’ horses.

“There are a few horses ridden by club members that are leased and boarded at neighboring barns,” she says. “Some of those riders have tack that they borrow from the horse’s owners, buy themselves at tack sales, or are supplied through generous donations from those in our horse community.”

Ableidinger also gives weekly lessons to her 4-Hers—for free. She even picks up and drops off some of her club members so they can come to meetings and lessons.

“It’s pretty much my full-time job even though I’m a volunteer,” she says. “But I love what I do, and it’s reward enough to see our club members learn and grow in their horsemanship and witness how much they enjoy being a part of the club.”

Breed of Choice

Most of the horses in the barn are Gypsy Vanners; the Ableidingers bought their first two Gypsy yearlings in 2015 and never looked back.

“They have the best temperaments,” Ableidinger says. “They are like big puppy dogs that want to be with you, and they will work very hard for their rider or handler.”

While it’s common to see children with Gypsy horses in the United Kingdom, Gypsy breeds fetch a high dollar in the United States.

“The cost of one of these horses makes them unaffordable for youth,” Ableidinger says. “There are very few youth riders in the breed in our country. We wanted to change that. We felt passionate about putting these amazing horses into a program for youth to enjoy and work with.”

Back in the Saddle

Since their yearlings were too young, Kimberlee Tilton of LCR Gypsies gave them a Gypsy mare, Mia, as a care-lease to use as the first project horse. The following year, the

Ableidingers bought her. They now have six Gypsies in the program, along with a few draft crosses and several Quarter Horses.

Ableidinger also had a personal dream to ride again. In 2019, she and Mia competed at the Oregon State Fair in a freestyle class with her 4-Hers cheering her on.

Decked out in lime green (the Lyme awareness color), they competed to Avril Lavigne’s “Head Above Water,” a song Lavigne wrote about the devastating disease. It was a completion of a dream for Ableidinger, and the smile on her face as she performed said it all. She was back in the saddle and sharing her love with youth.

Her life has purpose again, making the hard days that she still has due to Lyme disease easier to handle. As for the 4-H Horse Project youth, she and Scott are providing priceless experiences they will never forget.

This article about the 4-H Horse Project appeared in the October 2021 issue of Horse Illustrated magazine. Click here to subscribe!

The post Overcoming Lyme Disease to Give Back to 4-H Youth appeared first on Horse Illustrated Magazine.

When I was recently in Massachusetts walking in the woods with my friend and her dog, a constant refrain I heard was, “Stay on the path! Do not venture into the grass or the woods.” The reason: ticks. Perhaps you’ve been similarly advised to be particularly observant in looking for ticks after riding your horse through woods or fields. This is good advice for those of you living in areas where Lyme disease is present. Lyme disease is caused by infection with the bacteria species Borrelia burgdorferi. The disease is passed to horses, people, and dogs through insect carriers, namely ticks. 

The particular culprits are the Ixodes ticks (black-legged and deer ticks), which flourish in the Northeast, mid-Atlantic, upper Midwest, and in pockets of the Northwest. The disease is named after Lyme, Conn., where it was first identified in 1975. 

Climate change is expanding not only the range of the Ixodes ticks but also their numbers as they thrive due to extended warm seasons in many areas; ticks favor temperatures above 40 degrees Fahrenheit. More cases of exposure to Lyme disease are documented each year, and almost every state is now seeing cases in people and dogs, meaning that horses, too, can become infected.

How is it Contracted?
Currently there is only a vaccine for dogs, so protection for your horse is based on knowing how the disease is contracted and how to avoid tick bites. Not all horses bitten by an infective tick actually develop the disease, but they do develop antibodies, which are identified through testing.

The areas of the country where Lyme ticks are widespread are also home to white-footed mice and gray squirrels, birds, and large wild mammals (like deer) that serve as a reservoir for Borrelia bacteria. When Ixodes ticks obtain a blood meal from an infected mammal, they can then spread Borrelia bacteria to the next animal they bite. 

One bit of good of news is that transfer of bacteria from a tick bite to a horse generally requires about 24 hours of tick attachment. Finding and removing ticks immediately improves the chances that your horse won’t develop an infection. If a tick is present for longer than 24 hours, Borrelia spreads through the horse’s connective tissue and into the blood to cause systemic infection.

Blood tests are able to detect antibodies that indicate exposure, but such tests are not reliable until three to four weeks following a tick bite. Exposure does not always mean a horse develops active infection. The experts recommend testing only horses with clinical signs that point to Lyme disease.

Treatment
Treatments for horses come from multiple sources: human treatment guidelines, testing the B. burgdorferi bacteria in the lab to see which antibiotics kill it or limit growth, as well as anecdotal reports. In general, tetracycline and derivatives, as well as penicillin and cephalosporins, are used to combat Lyme disease infection. 

There haven’t been enough clinical trials to evaluate which drugs best treat the myriad of clinical signs associated with Lyme disease. While some drugs may work well in humans, oral medications work very differently in humans and horses, so using human treatments is not reliable for horses. 

Length of treatment time is also not well-defined. Current recommendations suggest basing treatment duration primarily on the horse’s clinical response, and to a lesser extent on decline in blood antibody levels. Horses may test positive for Borrelia antibodies for months, and even years, despite aggressive and prolonged antibiotic treatment and recovery.

The longer a horse has an active infection before being treated, the less successful the treatment will be. There’s also a poor prognosis for horses that have developed neuroborreliosis. Lyme-induced uveitis also has a poor prognosis for vision restoration. 

It’s likely that Lyme disease is overdiagnosed in endemic areas. Exposure to the bacteria does not guarantee that a horse will develop clinical disease. For horses that test positive to Borrelia antibodies, it’s important to exclude other potential causes before starting antimicrobial therapy.

Prevention
Tick control is essential to prevention. Check your horse often and remove ticks as soon as possible. Environmental control is helpful through landscaping practices. Ticks prefer woodland habitats and areas abundant with tall grass and piles of leaves, especially at the boundaries of these areas. 

Fewer ticks are found in areas that are clean, dry, sunlit, regularly disturbed, and well-maintained. When possible, keep horses away from wooded areas and transition zones into wooded areas. Mow pastures and clear away leaves and debris. Exclude deer as much as possible from areas with horses. 

However, ticks can still survive in stalls and pastures even during cold temperatures, although they don’t do well with freeze-thaw cycles. Inspect your horse daily year-round if you live in an area endemic with Lyme disease. 

Meticulously check the belly, groin, under the tail and mane, beneath the chin, within the armpits, and the lower legs. While ticks can attach anywhere, they are often found in softer areas with finer hair. 

If you find a tick on your horse, remove it in its entirety, taking care not to leave any mouthparts embedded in your horse’s skin. Wear gloves and grasp the tick’s mouthparts with tweezers as close to the skin as possible. Apply gentle upward traction without twisting. Once removed, you can destroy the tick by any number of methods: a) with flame; b) immersion in a jar of rubbing alcohol; or c) flushing it down the toilet. 

Application of insecticides, like permethrin or cypermethrin wipe-on or spray products, shampoos or powders to your horse’s hair coat are helpful, although there is no guarantee that insecticides prevent ticks from attaching, biting, and transmitting disease. Topical insecticide treatments are effective for only four to eight hours and need frequent reapplication. 

Off-label use of canine Lyme disease vaccine has been attempted in horses, but protective antibody levels drop significantly within four months.

The Bottom Line
For areas of the country where Lyme disease is prevalent, you can still enjoy riding your horses out on wooded trails and through the fields. Just be aware that you’ll need to spend extra time going over your horse carefully to locate and remove any ticks that may have shared the ride with your horse or attached while your horse was out in pasture. Prompt removal within hours is key to curtailing risk of infection with Lyme disease. 

NANCY S. LOVING, DVM, is a performance horse veterinarian based in Boulder, Colo., and is the author of All Horse Systems Go.

This article originally appeared in the July 2019 issue of Horse Illustrated magazine. Click here to subscribe!

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