When I first graduated as a Doctor of Veterinary Medicine, we saw only the rare tick in our area, and it was almost always on a pet that had travelled south, where ticks have always been common. But over the last two decades we have begun to see more ticks on our patients, and in the past couple of years this number has risen astronomically. Many of these pets have not left the province. At one time, the majority of ticks that we saw in Ontario were American Dog Ticks, whose proper name is Dermacentor variabilis. But we are now finding more deer ticks, or Black-legged ticks, (Ixodes scapularis), which are the ticks that carry Lyme disease. In the province as a whole, these two ticks are now seen in almost equal numbers. The deer tick has become established along Lake Erie, Lake Ontario, around the Thousand Islands. Research has also shown that the number of areas where Lyme disease has become established in Manitoba, Ontario, Quebec, New Brunswick and Nova Scotia have increased from 10 in 2009 to 22 in 2012! To make matters worse, recent research has shown that ticks are spreading out from these established areas in a radius of 35-50 km per year.
Ticks have a complex life cycle, requiring 3 host animals and up to 2 years to complete their maturation from egg through larva and nymph to adult. Most ticks in the different stages are found in wooded areas or along trails – but ticks are rarely found in trees. The parasitic stages of the tick wait on blades of grass or shrubs for a host animal to pass by. When the animal or human brushes by, the tick climbs off the vegetation onto the host. Ticks cannot jump, they only crawl. Once they get onto the host, they will latch on and start sucking blood, and may stay attached for several days. It can take up to 24-48 hours for a tick to transmit the agent that causes Lyme disease. Other diseases that can be transmitted by ticks are rarely found in Ontario at this time, but for some of these, it only takes a few hours for your pet to be infected.
We have traditionally believed that the risk of contact with ticks peaks in the summer months. However, we now know that the deer tick becomes active at 4°C. Over the past 5-6 years, there have only been a handful of months when the temperature never climbed above 4°C. This means that, although we don’t see ticks 365 days of the year in Ontario, we can see them 12 months of the year!
In 2016, between climate change and the effects of El Nino, we in Ontario have experienced one of the warmest winters on record. As health care providers, we are very worried about how this will affect the spread of ticks in our area. The good news is that we have very effective tick control products available for use on our furry friends, as well as a vaccine to protect our dogs against Lyme disease. Give us a call and we can talk about our recommendations for your pet. Or check out our articles on Ticks and Lyme disease, under the PET HEALTH tab on our home page.
Dr. Cheryl Yuill