Search
  • Dr. McKenzie

Tick Talk


As I watch the snow swirling outside, and huddle within several layers of clothing for warmth, it is hard to think about ticks. However, the wonderful Pine Ridge Team told me it is March 1st, and I need to break out the tick-talk. Right they are.

Historically, February is the only month our clients don’t report finding ticks on their pets. This year didn’t break this trend - no ticks in February. However, March is always a different story. Usually temperatures are warm enough in March, and we have quite a few ticks showing up on pets. Ticks become active as soon as temperatures are above zero celsius. Ticks are most active from 4-20 degrees celsius (39 to 68 degrees Fahrenheit). As such, we see peak tick seasons Spring & Fall, often before & after most other biting insects are out. This is why ticks are often a surprising find while it is still chilly outside.

Surprisingly for such a small insect, ticks do not die in the winter. These little creatures can actually live 2-3 years. The vast majority of ticks we see in Ontario are black legged ticks, also called deer ticks, or what entomologists formally call Ixodes scapularis. These ticks are not terribly picky - they will feed on practically anything with blood - though they have different preferences at different life stages. The very tiny larval ticks, for example, prefer rodents as their first meals. The rodents are actually the reservoir for the dreaded lyme bacteria (Borrelia burgdorferi). It is shocking how tiny ticks can be. The larval ticks are only the size of the period at the end of this sentence. The nymphs are the next life stage, and they are only slightly bigger, maybe a ( . ) with legs. The nymphs will feed on deer, pets and people. Yikes! I admit, this freaks me out. Would I notice something the size of a freckle on myself, my child or my pet? I don’t know. I don’t think most of us would….I don’t believe anyone has ever brought in a nymph to Pine Ridge Veterinary Clinic for identification. Those nymphs have already likely fed on rodents, and potentially already have lyme bacteria. Even the unfed adult ticks are pretty darn small. When I look at pictures of tiny ticks & think about my hairy black dog - it reminds me why we recommend testing pets for tick diseases every year. There is no way I can be certain Dizzy has never had a tick feed on her, but she has never tested positive for any tick diseases. Dizzy also takes her year-round tick preventative product, and is vaccinated against Lyme disease.

I often call ticks “slow mosquitos”. This is because like a mosquito they come only for a blood meal, then they leave again. Unlike a mosquito, they feed for many days; an adult female tick can feed for 5-7 days. Yikes, again! They don’t want to live on us or our pets, they just want to dine & dash. Also like mosquitos, ticks give their victims a bit of “freezing” - they inject some numbing chemicals at the bite site so that we don’t feel them. Tricky customers. Another reason for good tick prevention measures - it is very unlikely you, or your pet, will even notice you have a tick feeding on you. They don’t hurt or itch, but they do expand...with your BLOOD!!!!!!*^%$&^%#$

As you likely know, ticks can carry diseases. World-wide there are lots of ticks, and lots of tick borne diseases. Thankfully in Ontario we currently only have a very few endemic ticks, and only three known diseases that they can carry here that affect dogs: lyme disease, ehrlichia and anaplasma.

At this time, Ontario ticks do not carry any diseases that can affect cats. It is important to be aware that if you travel outside Canada with your pet, the risk factors can be much different. If you do travel with your pet, please always tell us when you are in for your consultations. Our parasite prevention and disease prevention recommendations may change if we know you will be visiting other countries - this includes our neighbour the USA.

So just how many ticks are out there anyway? And how many of them actually carry any disease at all? I have no idea. I don’t think anyone can truly answer that question - though many are trying. For many years, Health Canada had a passive surveillance system for ticks where veterinarians and medical doctors could submit ticks they found on patients, and the ticks would be tested for diseases of human significance if appropriate. This program ended about 18 months ago, I think mainly because it became apparent that the proverbial cat was out of the bag: ticks and lyme were here to stay, no further surveillance necessary. You can check out current public health maps showing endemic areas of lyme disease here: https://www.publichealthontario.ca/-/media/documents/lyme-disease-risk-area-map-2018.pdf?la=en

Who else is trying to figure this out? A group of vets at the Ontario Veterinary College in Guelph, and the Atlantic Veterinary College in PEI. They have their own passive surveillance study set-up called the Canadian Pet Tick Survey. Anyone who finds a tick on a pet can submit a record on their website: https://www.petsandticks.com/ .

The Pets and Ticks website is also a great resource for pet related tick-maps, and general tick information. (You can also see a super nerdy picture of Dr. Scott Weese holding a petri dish like a mad scientist - I admit, I am pretty jealous of that photo, I might have to steal that pose for a future blog shot. All I’ve got is me hugging ragweed & cuddling kittens). In 2018 they had 519 ticks reported, in 2017 they had over 1500 ticks reported! Remember: this is passive surveillance; ie. this represents only the small percentage of the population who know about this website already & wish to report ticks. It doesn’t represent all the hundreds (thousands?) of ticks people yank off & throw in the garbage… or all the ticks we never knew were there in the first place.

The other resource we have is the laboratory we use called Idexx. They also have a passive surveillance study, but theirs is geared towards diseases. On the Idexx website, veterinarians can report if they have patients who test positive for certain diseases. They are currently tracking numbers and locations for 3 tick diseases (Lyme disease, ehrlichia and anaplasma) as well as Heartworm and Leptospirosis (which are not tick diseases). You check out their maps at: http://www.petdiseasereport.com/content/prevmap.aspx .

Again, passive surveillance issues: vets might not report their positives, vets are using different labs, plus all the positives that are never tested/found. So, I look at the idexx statistics as “tip of the iceberg”. In Ontario in 2018 Idexx reported 930 lyme positive; 87 anaplasma positive; and 105 ehrlichia positive test results. Kylie here at Pine Ridge Veterinary Clinic narrowed down the search to within 50 km of Cobourg and found that of these 17 lyme positive, 2 anaplasma positive, and 1 ehrlichia positive test results were local to us. Thanks Kylie! Food for thought.

I do fall into the “knowledge is power” camp. It was great that the team poked me out of my winter slumber to think about ticks again. As soon as this snow melts I will be out in the garden puttering with my weeds again, and writing this blog helped remind me to pull up my tick-repellent socks over my pants before I get muddy, and give Dizzy her tick prevention too.


65 views

(905) 372-2721

(905) 372-4219

483 Ontario St, Cobourg, ON K9A 3C1, Canada

©2017 BY PINE RIDGE VETERINARY CLINIC. PROUDLY CREATED WITH WIX.COM