The best times we spend with our horses take place outdoors. That means we need to be aware of potential health concerns, including the unpleasant fact that tick-borne disease is increasing.
Ticks are adapting to climate changes. Regions with a high deer population typically have a higher number of ticks because deer are hosts to multiple tick species. Many horses travel to different areas of the country for competition, exposing them to ticks they don’t normally encounter at home.
“Ticks and the pathogens they carry are increasing in number and spreading to new areas,” says Brian Herrin, DVM, PhD, assistant professor of veterinary parasitology at Kansas State University College of Veterinary Medicine. “The Centers for Disease Control (CDC) has issued a statement warning about the increase in vector-borne diseases over the coming years.” Herrin has been instrumental in launching a nationwide surveillance study with the university to create a baseline for the most common ticks found on horses in the United States.
A new invasive tick species, the Asian longhorned tick (Haemaphysalis longicornis), has been found in multiple states and locations. “It appears that the Asian longhorned tick is here to stay,” says Herrin. “We still don’t know if it brought any pathogens from other countries or if it can transmit any of our existing diseases.” He adds that a group at the University of Georgia, Southeastern Cooperative Wildlife Disease Study, is tracking reported cases of this new tick.
The main tick-borne diseases that can affect horses are:
- Lyme disease
- Equine piroplasmosis
These diseases are diagnosed through blood testing,but reaching a specific diagnosis can be difficult because tick-borne diseases are sometimes present with non-specific indicators, so veterinarians often have to consider numerous possibilities. “In the horse, Lyme disease (which can also affect humans and dogs) is probably the most common tick-borne disease,” says Herrin.
Antibiotics are typically used to treat anaplasmosis and Lyme disease. After treatment with antibiotics, a horse infected with Lyme disease may never show symptoms again, but it’s possible the animal may relapse in the future.
“The U.S. has adopted a piroplasmosis-free stance, but the challenge is that horses travel to and from other countries,” Herrin observes. “There have been a few cases of equine piroplasmosis in the United States in the last 10 years.”
Treatment for piroplasmosis is based on the species of parasite involved, but the drugs used, can have adverse side effects and a definitive cure is unlikely.
In the United States, a case of equine piroplasmosis must be reported to state and federal veterinarians, and any horse being treated for the disease is enrolled in the United States Department of Agriculture (USDA) treatment program, which requires strict quarantine and routine testing.
Horse owners should be aware that ticks don’t have to transmit disease to cause a problem. “There can be large inflammatory reactions that leave open sores after ticks detach or are removed,” notes Herrin. “Those areas can be treated like any open wound and cleaned appropriately. The key is also to keep the flies away, so using a fly repellent meant for wounds can also help reduce the risk of a secondary infection. If the wound persists, then a veterinarian may need to clean and debride the wound.”
Step Up Protection
There are no vaccines currently labeled for use in horses for tick-borne diseases, although a vaccine for Lyme disease is available for dogs.
“There’s a study on the use of the canine Lyme vaccine in horses that showed the efficacy was low and did not last very long,” says Herrin. Such off-label use would not be recommended by veterinarians.
Your best plan for preventing infection of tick-borne bacteria, viruses or parasites, that may cause disease, is to limit exposure to ticks — for both you and your horse.
Woods and thick, tall vegetation are prime habitats for ticks. Contrary to popular belief, ticks don’t drop out of trees. Rather, they climb up grass and vegetation, and then reach out using their front legs to grab onto their desired host, a tactic known as “questing.”
Ticks prefer shade and shelter, so they tend to avoid crossing hot, sunny areas with low or little vegetation. Think of it this way: the more sun in an area, the less inviting it is for ticks.
Keep yards and pastures mowed and don’t allow vegetation, weeds or leaves to accumulate. If your horse is turned out in an area that contains thick trees, mow a 10-foot strip of grass between the trees and the open pasture to help maintain a boundary that will be uninviting for ticks.
Although ticks differ from other pests like flies and mosquitoes, you can still use some of the same layered approaches to protecting your horses against them. Applying both long-lasting spot-ons and spray or wipe-on repellents will help protect your horse.
Horses that spend all or most of their time on pasture can have more exposure to ticks than stalled horses and can benefit from a spot-on repellent. Even if you’re using a spot-on, Herrin recommends regular full-body “tick checks,” especially if the horse has been in an area with tall vegetation or woods.
Up the protection factor by using a spray repellent labeled “effective against ticks” when you’re out riding.
Experts recommend wearing light-colored clothing to make it easier to see if a tick is crawling on you. To deter ticks from crawling up inside the legs of your pants, tuck your pants into your socks.
If your dog accompanies you on rides, help protect them against ticks by using a spray repellent that’s safe for canines.
Even when using repellents, you should always do a full-body check of your horse, dog and yourself to check for ticks right after you’ve been in areas where they can be found.
There’s a common belief that a tick can’t transmit disease unless it’s attached for 24 hours, but Herrin says this theory evolved from studies on just one pathogen.
Take steps to guard against ticks year-round, not just during warm weather. Ticks are highly adaptive, and many species can insulate themselves in leaves and vegetation beneath snow until they find a host to feed on.
“A lot of people associate ticks with flies and mosquitoes, focusing on protection in spring and summer, but there are many tick species that are active in the winter, even when snow is on the ground,” cautions Herrin. “In the Northeast, fall and winter are peak activity times for adult Ixodes ticks that carry Lyme.”
The key to tick protection is awareness and vigilance. Be smart and take precautions so concerns about tick exposure won’t interfere with what you love most.
Courtesy of Stable Talk by Farnam