Dr. Holly Jacobson: Don’t cool off on flea, tick prevention


“Oh the weather outside is frightful,” or so the song goes. Let’s face it: It’s winter, it’s Indiana, and it’s darn cold outside. It’s the season to remain indoors. And as long as our pets are indoors with us, we don’t have to worry about pesky ticks, fleas, and the mosquitoes that spread heartworm disease. It’s the perfect time to save a little money and lay off those flea, tick and heartworm preventatives, right? Wrong.

Trust me, I like to save a few pennies whenever I can, too (especially when those Christmas credit card bills hit). But if you’re concerned about your pet’s health and want to avoid an uncomfortable parasite infestation in your home, winter is not the time to scrimp on flea, tick and heartworm preventatives.

First, some common sense. If the cold temperatures of winter destroyed all fleas, ticks and mosquitoes, then how could they reappear with a vengeance in the spring and summer months? The answer is that cold temperatures do not necessarily kill all parasites in all their life stages. While an adult flea, for example, will die after extended exposure to cold below 31 degrees Fahrenheit (-0.555 for us Celsius nerds), a pre-emergent adult in its cocoon will remain dormant until it senses warmer, spring-like temperatures. Then it will emerge and begin the remainder of its life cycle — including biting your pet, riding her inside your home, and laying eggs for the next generation.

“But surely, the winter months are too cold for this to happen?” you ask. Well, let’s look at the facts. In Greenfield during January 2021, we saw no less than seven days with high temperatures of 40 degrees or more. One day, the high was 49 degrees. These temperatures provide more than ample opportunity for adult fleas to emerge.

The same holds true for blood-sucking ticks, including the ones that cause Lyme disease, and whose life cycles last two to three years. They are evolved to survive over winter months by hiding their dormant larvae in leaves and other debris. But when the temperatures rise, so do the larvae, who will feast on your pet (and you) if they are given the chance.

Now imagine that your pet brings these parasites into your home, where the temperature is a cozy 70 degrees, no matter the time of year. You have just created the ideal conditions for them to live year-round in the tiny nooks, crannies and crevices of your house. Now, it’s not just your pet’s problem. It’s your problem! Good luck getting rid of them.

“OK. What about mosquitoes?” you ask, “There are no mosquitoes to spread heartworm disease in winter.” Sorry, but wrong again. Adult mosquitoes will hibernate once temperatures fall consistently below 50 degrees. But they come out of hibernation when temperatures rise. So, let’s say that one of those mosquitoes bit a heartworm-infected dog before going into hibernation, and then, on that warm day in January 2021, woke up to bite your dog. If unprotected, your dog could very well contract heartworm disease. Now your dog has heartworm disease, and even if you had protected him with prevention the other nine months of the year, you are looking at thousands of dollars in treatment to save his life. And since you discontinued prevention, no drug maker will be willing to assist you with the cost of the treatment.

So, the obvious answer here is to continue flea, tick and heartworm prevention throughout the entire year. An ounce of prevention is truly worth a pound of cure in this case. The discomfort and cost associated with ridding your pets, family and home of these parasites far exceeds the price of a monthly preventative. Your pet deserves no less.


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