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Ticks and Lyme Disease

By Dr. Patricia Lechten

The incidence of ticks seems to be on the rise in Ontario. This is creating concern among many pet owners, primarily due to the fear of ticks carrying Lyme disease. Although ticks can transmit diseases, they are usually nothing more than a nuisance. The best approach is to prevent them from embedding, and if embedded, to remove them quickly.

Ticks are skin parasites that feed on the blood of their hosts. Ticks like motion, warm temperatures from body heat, and the carbon dioxide exhaled by mammals, which is why they are attracted to dogs, cats, and people. Ticks wait for their host on the tips of grasses and shrubs. When the plant is brushed by a moving animal or person, the tick quickly lets go of the vegetation and climbs onto the host. Ticks can only crawl…they do not jump or fly. 

Most ticks found on dogs are ‘hard’ ticks. They have a hard shield just behind the mouthparts (sometimes called the ‘head’). Unfed hard ticks are shaped like a flat seed.  Female ticks engorge with blood when attached and can significantly increase in size.  Ticks do not burrow under the skin. Most types of ticks require three hosts during a two-year lifespan. Each tick stage requires a blood meal before it can reach the next stage.

The tick bite itself is not usually painful but the tick can transmit disease or cause tick paralysis. It takes several hours to days for an attached tick to transmit disease, so owners can usually prevent disease transmission by looking for and removing ticks on a regular basis.

Residual insecticides can be used to prevent ticks from attaching. Unfortunately many of these products are not available in Canada. Revolution (a spot-on heartworm/flea preventative) is labeled for one kind of tick. Advantix is a spot-on that repels and kills fleas, ticks, mosquitoes, and some flies. It is highly toxic to cats, so cats should not be allowed near dogs while the product is wet and should not be allowed to groom dogs in the area the product was applied.   Preventic collars have some effectiveness against ticks. The collars do not keep all ticks off, but they do discourage ticks from implanting or staying on. The collar might be somewhat more water resistant than a residual insecticide, so if your dog swims, the collar might be a better choice. All of these products either kill the tick or cause it to drop off prior to the 48-hour deadline necessary for the transmission of Lyme disease. 

Remember to check for ticks especially after walks in woods and tall grass.

The best way to find ticks on your dog is to run your hands over the whole body. Check for ticks every time your dog comes back from an area you know is inhabited by ticks.  Ticks attach most frequently around the head, ears, neck and feet, but can be found anywhere on the body. 

The safest way to remove a tick

The safest way to remove a tick is to use rubbing alcohol and a pair of tweezers. Dab rubbing alcohol on the tick and then use the tweezers to grab the tick as close to the dog’s skin as you can. Pull slowly and steadily trying not to leave the tick’s head embedded in the skin. Don’t squeeze the tick because it might inject some disease-causing organisms.  Risk of disease transmission to you, while removing ticks, is low but you should wear gloves if you wish to be perfectly safe. DO NOT apply hot matches, Vaseline, turpentine or nail polish because these methods for removing the tick do not work and are not safe for your dog. Once you have removed the tick, kill it by putting it in rubbing alcohol or insecticide. 

After you pull a tick off, there will be an area of inflammation that could look red, crusty, or scabby. The tick’s attachment causes irritation. A mild topical antibiotic may be applied, but usually is not necessary. The inflammation should go down within a week. 

Lyme disease in dogs

Lyme disease is a systemic infection caused by a bacterium called a spirochete. The bacterium is carried by several species of ticks, most commonly the Deer tick or black-legged tick. In Ontario, blacklegged ticks are more commonly found along the north shores of Lake Erie, Lake Ontario, and the St. Lawrence River. In general, black-legged ticks infected with Lyme disease are much more common in the United States along the Atlantic seaboard from Maine to Virginia and in Minnesota and Wisconsin than they are in Ontario. 

Dogs become infected when they are bitten by an infected tick. The tick needs to feed on the dog for more than two days before infection occurs. The tick itself becomes infected by feeding on infected mice, birds, deer, and other animals. Direct transmission of Lyme disease from one dog to another has not been reported, even when infected and uninfected dogs have lived together for long periods. Transmission of Lyme disease from dog to people has not been reported.

Some dogs infected with Lyme disease do not show any signs of illness. In dogs that get sick, the signs may be vague and not appear for several months. The most common clinical sign is lameness, but a small percentage of dogs develop severe, life-threatening kidney disease. Lyme disease can be treated with a variety of antibiotics. In dogs, Lyme disease is generally a minor infection not nearly worthy of the attention it has received.  Lyme disease in the dog is an infection from which 90% of infected dogs will never get sick and the 5 or 10% that do get sick can be easily treated with a safe, inexpensive course of antibiotics.   

There is a vaccine against Lyme disease available. Not all dogs need to be vaccinated and the decision to vaccinate would be influenced by the level of Lyme disease in the areas the dog lives in and travels to, the amount of time the dog spends outside, and the potential for side effects from the vaccine. 

REMEMBER - although ticks can transmit diseases, they are usually nothing more than a nuisance. The best approach is to prevent them from embedding and, if embedded, to remove them quickly.

By Dr. Patricia Lechten is the owner of Allandale Veterinary Hospital in Barrie, Ontario and a wonderful and supportive friend to Golden Rescue.