As the Asian Longhorned tick (Haemophysalis longicornis) continues to spread in the US, we wait for it to make an appearance in Canada. This “exotic tick” was introduced to the US from Asia possibly a while ago, but was only first detected in 2017 in New Jersey.  It has since clearly established itself as a resident tick species in many states. It’s pretty much inevitable that it will make it to Canada, with southern Ontario or Quebec being the likely entry points.

This tick is a concern for a few reasons. One is that it’s an aggressive feeder. When you combine that with the biological quirk of females being able to reproduce without mating, you can get massive infestations of these voracious feeders on some animals, to the degree that species as large as cattle can die from blood loss.  (This is similar to what the winter tick (Dermacentor albipictus) can do to moose.)

Haemophysalis longicornis can also be the vector of a various infectious diseases of people and animals. Which diseases this tick can transmit in North America is an current area of investigation, since importation of the tick doesn’t necessarily mean all the potential diseases were also imported. We don’t know the extent of that risk yet.

So, what about companion animals?

There are a few issues to consider with dogs and cats when it comes to this tick as well. One is the potential for health effects from massive tick burdens. Hopefully the risk of serious effects from that is lower than in wildlife and livestock since pets are usually monitored more closely, but it’s still a concern. Disease threats are still pretty unclear at the moment but can’t be dismissed.

The other issue is the potential for pets to act as sentinels for this tick. If you look at the USDA’s latest Situation Report on H. longicornis (including the images above), dogs are #3 on the list of most commonly identified hosts, after the environment and white-tailed deer. This is the case despite any formal surveillance directed at this tick in dogs. It’s not particularly surprising since dogs can spend time in tick-rich areas, running through sites where ticks are looking for a host. As a low-to-the-ground haired species, they can pick up ticks quite easily, and a tick on a dog may be more likely to be spotted than a tick on most other species.

Back to Canada…

The fact that this tick entered the US first has given us a head start for planning, and there are various activities underway to optimize the response to this tick when it’s found, including detection, identification, testing, and communication. The key first step, though, is finding the tick, and finding it as early as possible. Here’s where dog (and cat) surveillance can come in. Since dogs can be such great sentinels for ticks, it’s quite possible we’ll find it first on on dogs – if we’re looking, and communicating.

There are a variety of ways this kind of detection might happen, such as:

  • An owner finding a tick on their dog and taking it to their vet, who realizes it’s different than a typical tick and sends it off for further investigation.
  • A submission to a surveillance program such as our PetTickTracker or, for some provinces, eTick.
  • A tick found as part of ongoing pet surveillance such as our Canadian Pet Tick Survey (active surveillance through participating vet clinics) or our Lifetime Lyme Study.

Tick surveillance is a great example of the potential impact of citizen science. A curious veterinarian or pet owner might be the first to find this tick, allowing a quicker intervention than if we relied solely on traditional sources.

Tick image: