As the sun hovers low, elongating shadows across the pasture, and crickets fill the air with their melodic hum, horses revel in vast open spaces. Amidst the swaying grass and gentle flicks of their tails lies a hidden danger, transforming this picturesque scene into a nightmare for horse owners.
This silent menace is none other than the insidious threat of tick-borne diseases affecting our equine friends.
Borrelia burgdorferi, Equine piroplasmosis, and Anaplasmosis are not common household names, but within the close-knit equestrian community, they are dreaded. The names might not roll off the tongue with the same ease as “West Nile” or “Rabies,” yet the impact they can have on horses and horse owners is no less severe.
Lyme Disease: The infection of the bacterium Borrelia burgdorferi can often masquerade as the rigors of everyday horse life. Dr. Matthew W. Lovell, DVM, Owner and Founder of Tennessee Equine Hospital North states, “B. burgdorferi can cause certain documented clinical signs including a neurologic form of meningitis, inflammation of the eye, nodules on the skin often around a tick bite, and bursitis. Undocumented clinical signs include stiffness, behavioral changes, weight loss, shifting leg or intermittent lameness, and hypersensitivity to touch or stimulation.”
Equine Piroplasmosis: “Infection by the single celled parasites: Theileria equi or Babesia caballi, transmitted by ticks, causes clinical signs in all equine species, and is about 50% fatal,” according to Dr. Lovell. He continues to explain that, “horses with mild signs may show reduced or absence of appetite, weakness, and exercise intolerance. More severely affected horses can have fever, anemia, jaundice, weight loss, labored breathing, swollen abdomen, colic, and sudden death. Horses that survive become lifelong carriers but may appear normal and can spread the disease.”
Anaplasmosis: Formerly known as “Ehrlichiosis,” Anaplasmosis shares some symptoms with equine piroplasmosis, such as fever and anemia. Dr. Lovell states, “bacterium, anaplasma phagocytophyilum, invades white blood cells and alters their function and causes certain clinical signs. Severity of clinical signs seems to be dependent on the horse’s age. Young horses under a year-old often show fever only. Signs in horses one to three years old can include fever, mild limb swelling, and lack of coordination. Adult horses can show fever, poor appetite, depression, reluctance to move, limb swelling, and jaundice. Abortions are rare but can occur in any stage of gestation. Death is rare and most horses recover over a period of two to three weeks, but death can occur from secondary disease or complications.”
Treatments and recovery
Proper diagnosis can be challenging, particularly in the early stages of these diseases. Lyme disease, specifically, has been called “the great imitator” for its ability to mimic other common equine illnesses. Vet intervention is critical, involving a thorough physical examination and blood tests. For piroplasmosis, serologic tests and examination of blood smears are the most common diagnostic tools. Anaplasmosis is generally diagnosed through a blood test. The quicker you catch these illnesses, the better the chances of successful treatment.
Dr. Lovell states that treatment for lyme disease normally involves the use of long-term antibiotics. “Different classes of antibiotics have demonstrated effectiveness in treating Lyme disease, but studies show intravenous oxytetracycline followed by oral doxycycline or minocycline may prove most effective in preventing recurrence. I once treated an infected mare with 21 days of IV oxytetracycline followed by a 30-day course of minocycline followed by vaccination and felt the treatment was successful. Treatment protocols should be left up to your veterinarian based on their experience.”
In the case of Equine Piroplasmosis where horses that survive become lifelong carriers, Dr. Lovell states, “equine piroplasmosis can be treated and infected horses no longer require export from the US, euthanasia, or lifelong quarantine. Treatment can only be performed by an accredited veterinarian using an antiprotozoal drug with oversight from a federal or state veterinarian. This program has cleared most horses with the infection, though repeating the treatment has been necessary in some horses. Treated horses can be released from quarantine once thoroughly tested negative for EP.”
And according to Dr. Lovell, treatment for Anaplasmosis “generally consists of intravenous oxytetracycline for several days or intravenous oxytetracycline followed by oral doxycycline. Concurrent NSAID’s may be administered.” This treatment can shorten the course of the disease and prevent secondary complications and long-term illness.
Partners in Prevention
Prevention is always better than treatment, and with tick-borne diseases, this proverb rings truer than ever. There are several strategies to fortify your horse’s defenses against these ailments.
First, understand the ecology of ticks in your area. Knowing when and where your horse is most at risk can help you take proactive measures to mitigate the danger. Familiarize yourself with the types of ticks that are most commonly carriers of these diseases and recognize their distinct appearance.
Modifying the horse’s environment can significantly reduce tick exposure. This can include regular mowing of pasture grass, minimizing their time in wooded or brushy areas, and certainly avoiding known tick hotspots.
From topical applications to treated leg wraps, there’s a range of tick repellents on the market specifically designed for equines. Consult with your veterinarian to find the right product for your horse. Dr. Lovell advises, “use of permethrin containing repellant sprays or pour-on products reduce exposure to ticks.”
Regarding prevention of Lyme Disease he advises that, “Vaccination with off label use of a canine Recombitek Lyme vaccine has proven to offer protection for horses that have not been infected, and I have used the product post treatment, and in multiple horses on a farm where Lyme disease had been diagnosed.”
For EP he advises, “Always use a sterile, unused needle to draw up all medications and for all injections. Make sure all dental and surgical or tattoo equipment is cleaned and disinfected between uses. Administer only licensed blood or plasma products. Monitor the presence of ticks on horses and consult a veterinarian for their control and prevention. Contact a veterinarian if your horse shows signs of fever, jaundice, decreased appetite or weight loss.”
And concerning Anaplasomis Dr. Lovell states, “Since there is no vaccine for anaplasmosis, remove and destroy ticks as soon as possible. Check horses for early signs of illness or infection. Again, destroying tick habitat near your horse’s environment by keeping pastures clipped, clearing brush, and removing wood piles reduces exposure.”
Your veterinarian is your most important ally in the fight against tick-borne illnesses. They can provide guidance on vaccinations, run tests for disease if symptoms are present, and advise on the best course of action should your horse fall ill.
Owners must take on the day-to-day responsibilities of prevention. This includes staying informed about the risks, recognizing the symptoms of tick-borne illnesses, and diligently following through with the prevention tactics recommended by professionals. Regular grooming and responsible pasture management can be game-changers in reducing tick exposure.
