Living With Ticks in the Greater Toronto Area

It’s hard to believe summer’s over and we’re already into the fall. But while time flies and life marches on, we’re not yet out of the woods where ticks are concerned. In fact, the little nymphs that have summered in our province have all grown up and are now full-fledged young adults on a quest for their next meal ticket. They’ll be around for a while yet – typically well into November before they become dormant for the winter.

In Ontario, the tick we worry about most is the deer tick (Ixodes scapularis) – so-called because the adult prefers to dine on white-tailed deer (but you or your dog will do just as well if you’re within reach).

The deer tick (a.k.a. black-legged tick) has the potential to transmit a few diseases, but the one that’s increasingly making the news is Lyme disease. (You may recall that Canadian singer, Avril Lavigne, was diagnosed with it not long ago.) As we’ve stepped up our dialogue on this subject over the last couple of years (as more dogs have presented with a tick), we’ve learned that a few of our clients have a friend or relative who’s been diagnosed with Lyme disease at one time or another as well.

While Lyme disease isn’t yet endemic (that is, common) in the Greater Toronto Area, studies show that within 3 to 5 years of ticks establishing themselves in an area, they’ll be carrying the bacterium (Borrelia burgdorferi) that causes the disease. Well, we know we have deer ticks. Here’s one we removed from a patient in March.

And we know we have the rodent populations (notably the white-footed mouse) that carry Borrelia. And since rodents are the preferred host for deer tick larvae and nymphs, well…it’s not hard to connect the dots here. We’ve got it all: Migratory birds that bring in millions of hitch-hiking tick nymphs each Spring; a host for every stage in a tick’s life cycle (rodents, birds, deer, dogs, people, coyotes); rodents that carry Borrelia; warm enough weather and plenty of parks and woodland offering the cover of leaf litter to support each life stage.

So, with adult tick season about to peak again, this is a good time to review the information we posted in the Spring: Protecting You & Your Dog From Ticks. Keep in mind that as long as the temperature is above 4° C, a tick will keep on ticking. So as far as we’re concerned, tick season runs from March 1st to November 30th. Adults are active in the spring and fall, while larvae and nymphs are active in the spring and summer. And while each life stage has a preferred host, any blood meal will do.

One last thing. We have some really beautiful parks and conservation areas in Ontario that afford an opportunity to commune with nature, regroup, and escape the pressures of life. The ticks among us needn’t prevent us from continuing to enjoy our time outdoors.

The GTA at dawn…

Deer-spotting at the Rattray Marsh…

Dr. Iz Jakubowski