Ticks by Dr. Tiffany Rennick

Ticks! For most people, the very thought makes them shudder. These insects themselves are more than just a concern. Ticks can transmit serious diseases to pets and humans. Tick populations have been increasing in Ontario and with them, an increase in tick borne diseases.

The tick life cycle has 4 stages: eggs, larvae, nymphs and adults. At each of the stages from larvae to adults, the tick will attach to a host animal, feed and then fall off to develop into the next stage. The larval stage feeds on small mammals and birds, while the nymph and adult stages feed on larger hosts such as deer, foxes, raccoons and even humans, dogs and cats.

Since ticks are unable to jump onto their host like fleas do, they have developed an ingenious way to find animals to feed on.  Ticks sit on the tips of grass or leaves along well travelled paths. They hold onto their perch with their back feet and have their front feet outstretched waiting to attach to a host animal. They use body odours, heat, moisture and vibrations to sense when an animal is coming past them. This process of finding a host is called “questing”. Once they are on an animal they find a place to attach and feed, often places where the skin is thinner like behind the ear. To feed ticks grasp the skin, cut the surface and insert their feeding tube to suck in blood.  If a tick feeds on an infected animal it will ingest the organism in the blood. When the tick feeds on its next host, its saliva can enter the skin and transfer organisms to the new animal.

There are numerous types of ticks that each transmit different diseases.  Deer ticks (sometimes called black legged ticks) and American dog ticks are found in Ontario. The deer tick is the most concerning as it can transmit lyme disease and anaplasmosis to both pets and humans.  The American dog tick is the most common tick found on pets in Ontario, however it is uncommon for it to transmit disease.

  • Lyme disease is caused by a spirochete bacteria.  Clinical signs include fever, shifting leg lameness, lethargy, enlarged lymph nodes, and malaise.  More severe cases can cause inflammation in the joints (polyarthritis), kidneys (protein losing nephritis) and heart (carditis).  As of 2013, the Ministry of Health reports Lyme disease in the following areas: Point Pelee National Park, Rondeau Provincial Park, Turkey Point Provincial Park, Long Point peninsula (including Long Point Provincial Park and the National Wildlife area), Wainfleet bog region near Welland, Prince Edward Point, and the Thousand Islands National Park.
  • Anaplasmosis is caused by a bacteria that infects white blood cells.  Clinical signs include fever, anorexia, depression, and lethargy.

Treatment of these tick borne diseases requires courses of antibiotics.

Tick prevention is the most important part of preventing these diseases.

  • Avoiding areas with ticks – wooded or bush areas with long grasses and leaf litter
  • Check for ticks on people and pets daily.  Remove any ticks found or have them removed by your veterinarian
  • Use a topical chemical to repel or kill ticks on dogs  **cats are very sensitive to tick products, do not use them on cats**
    • Reduce ticks in your yard by removing leaf litter, clearing tall grasses, placing a 3ft wide barrier of wood chips or gravel between lawns and wooded areas to discourage ticks from migrating into yards, and mow lawns frequently
    • There is a vaccine for Lyme disease and it should be discussed with your veterinarian if you travel to known endemic areas

With ticks and tick borne diseases becoming an increasing concern in Ontario, our veterinarians and technicians would love to help choose the best prevention for your pets.