Where have all the ticks gone?
We've just updated our maps to include submissions up to the end of June. You might notice that there is not much different since our last update. That's because we haven't received many submissions over the last few weeks.
Take a look at the graph above. It shows the number of tick submissions by date since the launch of Pets and Ticks in mid-April. As you can see, there were a lot of submission in May, especially mid- to late-May. These were predominately adult blacklegged ticks and American dog ticks. Submissions continued until mid-June and then we see a noticeable decline.
Without a doubt there are some human factors at play here. School is out, holidays are in full swing, and it's highly likely that the Pet Tick Tracker is not your top priority.
Those reasons aside, we are still not surprised by these findings. To explain this, we need to talk about phenology. "Phenology" is a term used in the entomology world to describe the seasonal fluctuations in each life stage for each tick species.
Let's consider the blacklegged tick. In eastern North America (including Ontario, Quebec and the Maritimes), adult blacklegged ticks are active in the spring and fall (April, May, October, November). The nymphal life stage is most active in late spring / early summer (June and July) and the larval life stage is most active in late summer (August and September). For the American dog tick, we only see one peak of adult activity in the spring, followed by nymphal and larval activity from summer into fall.
Phenology is a function of many factors and we won't get into all of those details today. We mention it because knowing when specific tick species will be active helps us understand when risk is highest. We've added Tick Ecology Fact Sheets under Ticks 101 to provide you with key ecological information on the most common tick species in Canada, including seasonality.
So does this decline in tick submissions mean that we can let our guard down a bit? Unfortunately, no. If we think about Lyme disease, which is caused by a bacteria transmitted by the blacklegged tick, this time is still high risk. The nymphal life stage is still active and due to its small size, can be difficult to see and remove promptly. Nymphal ticks are not commonly submitted to passive surveillance programs (like the Pet Tick Tracker) because they are not routinely detected. That makes careful tick checks even more important.
Thanks for reading. Hope you're having a great summer!