We didn’t used to have to think about Lyme disease in Canada. Many of us would prefer not to think about it now, but as circumstances conspire to drive more and more infected ticks northward into this country every year, Lyme disease is rapidly becoming an illness that small farm operators no longer have the luxury of ignoring.
Ticks infected with the bacteria that cause Lyme disease are now found, to varying degrees, in every Canadian province. And while researchers acknowledge that there’s no region in this country that can be considered Lyme-free, there are known hotspots in southern Manitoba, New Brunswick, Nova Scotia, southern and eastern Ontario, southern Quebec and in many areas of southern and coastal British Columbia and Vancouver Island.
While media reports tend to focus almost exclusively on human cases of Lyme disease, it’s important for farmers to understand that the illness can also impact more than 300 species of animals, including some that are commonly found on small farms. This includes: cattle, chickens, dogs, goats, horses, pigs and sheep.
The good news is that most animals that contract Lyme disease develop mild symptoms that often resolve without treatment. The bad news is that those animals that go on to develop the full-blown illness can suffer significantly. And of all the animals on the farm, horses and dogs tend to suffer the most.
Horses at high risk
Horses make excellent targets for the ticks that carry Lyme disease.
Why?
Because adult female black-legged ticks (or Western black-legged ticks, if you’re in British Columbia) require a blood meal from a large mammal in order to reproduce. In nature, these ticks will often choose deer for that meal. On a farm, horses make the most attractive targets.
But being bitten alone isn’t enough for a horse to contract Lyme disease. There are some genetic gymnastics that need to be performed in order for the bacteria to successfully transfer from a tick’s saliva to a horse’s bloodstream and those gymnastics take time. There’s considerable debate over exactly how long a tick must remain attached to transfer a viable infection, but it’s generally agreed that removing the offending tick within 24 hours dramatically reduces the chances of a horse developing Lyme disease.
Unfortunately, few Canadian horse owners check their animals regularly for ticks, something that places horses at increased risk for contracting a Lyme infection.
And Lyme disease in horses can be a nasty business. Arthritis is the most commonly reported symptom. It can affect a single joint or multiple joints and the inflammation can either be chronic or it can come and go seemingly without rhyme or reason. Arthritis can also move from one joint to another so that a horse that may have been lame in a front forelimb one week may wind up being lame in a hind limb the next.
Although arthritis is the most common symptom of Lyme disease in horses, it isn’t the only one. Infected horses have also been known to suffer from chronic weight loss, decreased performance, depression, dermatitis, difficulty swallowing, encephalitis, eye inflammation, fever, head tilt, laminitis, lethargy, muscle tenderness and/or stiffness, and pseudolymphoma.
While most horses don’t develop serious symptoms, those that do can easily be treated with antibiotics, but only if the infection is caught in its early stages. Since Lyme disease is relatively new to Canada and since many of its symptoms are non-specific, it’s often not recognized until it has advanced to its the later stages, by which time treatment can be difficult and can last many months.
There is currently no vaccine to protect vulnerable horses. Therefore, it’s important to get in the habit of doing daily tick checks so that you can identify and remove any ticks before they have a chance to pass an infection on to your horses. Ticks most commonly congregate around the head, throat, and stomach, as well as under the tail and along the neck at the base of the mane, so those are the places you’ll want to check first.
Fido
It’s estimated that dogs are somewhere between 50 and 100 times more likely to contract Lyme disease than their human counterparts. Partly that’s because ticks would rather feed on dogs than on humans and partly it’s because dogs are much more inclined to frolic in the same long grasses, weeds, brush and wooded areas that ticks call home.
As with horses, infected dogs often develop no symptoms, but those that do suffer greatly. Symptoms can include intermittent or chronic arthritis that can shift from leg to leg, dehydration,
generalized pain, high fevers, lethargy, loss of appetite, swollen lymph nodes and sudden limping or lameness.
Many people expect dogs to have target lesions (red bull’s eyes like people get), but dogs never have this as a manifestation of Lyme disease.
If caught early, a Lyme infection can be easily treated with antibiotics. If treatment is delayed, the infection can cause extensive joint damage, cardiac complications, neurologic dysfunction and/or kidney failure. Untreated Lyme disease in dogs can be fatal.
Therefore, it may come as a relief to know that a vaccine is available for dogs. However there’s some controversy over its effectiveness and generally it’s thought that you should only consider having your dog vaccinated if you live in one of the Lyme hotspots mentioned above. If you live in a low-risk area or live in a high-risk area and want to avoid vaccination, you can ask your veterinarian to recommend a suitable repellent.
Ticks can attach themselves anywhere on a dog, but they have a particular fondness for the area in and around the ears, so that’s where any tick check should begin. Examining your dog for ticks whenever it comes in from outdoors and removing any ticks either before they’ve had a chance to attach or within the first 24 hours after they’ve attached will go a long way to protecting your dog from a run-in with Lyme disease.
Prevention is key
As with most things in life, prevention is key and the best way to keep your animals safe from Lyme disease is to keep them away from the types of habitat that ticks like best.
The highest concentrations of ticks tend to be in grassy areas next to forests or woodlots, so keeping your animals away from the pasture’s edge is crucial. They’re also commonly found in woodpiles, long grass, brush, weeds and rock walls, so cutting down vegetation and ensuring some distance between your animals and your firewood or stone structures will go a long way to keeping your animals Lyme-free. Be especially vigilant in the spring and fall when ticks are most active.
Although there is little research into their impact on Lyme disease transmission rates, chickens are known to eat their fair share of ticks, as are turkeys, guinea fowl and, to a lesser extent, ducks. Keep in mind that these birds will only control ticks in areas where they’re permitted to roam and will do nothing to control them in other areas of the farm, so if your chickens aren’t actually in your pastures, they won’t be benefiting your horses, cattle or goats.
Putting up fences to discourage deer is also a good idea. Deer attract ticks like magnets, so keeping deer out of your pastures and away from your animals will reduce their risk of contracting the bacteria.
And we can’t forget about mice, which are the preferred source of blood meals for immature ticks and as such play an important role in their lifecycles, so it’s important to keep the mouse populations on your farm under control.
A final note: people cannot get Lyme disease from their pets/livestock if their pets/livestock have it. Companion and farm animals are not the source of infection in people. But pets can bring unattached infected ticks into the household and then those infected ticks could attach on to people.
You’ve found a tick on one of your farm animals. What now?
- If the tick is still mobile, knock it off.
- If it’s attached, remove the tick with pointed tweezers by clasping its mouthparts and pulling it straight out without twisting the tweezers.
- DO NOT clasp the tick by its body, burn it off with a match, suffocate it with petroleum jelly, or pull it off with your fingers. All of these things can cause Lyme bacteria to be expelled into your animal and increase the chances they develop the disease.
- Place the tick in alcohol and take it to your vet for testing.
- Watch for signs of illness. Those signs may show up within a few days or they may take many weeks to manifest.
- Vanessa Farnsworth