Hi Bill,

Thanks for your question.

I understand where you’re coming from in that you really don’t want to be purchasing medication or putting it into your dog’s body unless you have to. You’re question is all about risk. Regardless of the season, you always have to consider cost and side effects of a medication before administering it and hopefully your veterinarian is giving you good unbiased information to allow you to make the best decision for you and your dog.

Ticks are becoming a great concern in many areas, and their incidence has climbed along with the incidence of Lyme disease. I really encourage you to take a look at our video about ticks and Lyme disease prevention. Around Toronto, Canada where I am located, ticks have increased in a number of locations. They are now endemic, which means they live here all year whereas 2-3 years ago they only migrated here on birds each season and then disappeared. So now I do see ticks on dogs in December and January. However, the risk is much lower in the winter compared to the summer months by a significant degree. I’ll see dozens of dogs with ticks in summer months and may see 1-2 dogs with ticks throughout the winter in my area.

Mosquitos and fleas are certainly less common to non-existent in the winter in most areas. The heartworm larvae can’t survive inside the mosquitos in consistently low temperatures during the winter. Fleas can’t either unless they are present inside infested homes with pets which is not that uncommon. They can transfer to your dog at parks through contact during play.

I recommend you discuss the incidence and risk of these parasites in your area with your veterinarian, then you can judge for yourself about the necessary course of action. We also have an article that may help you with your decision-making, entitled ‘Top Tips for Protecting Your Dog from Ticks This Spring‘.

I hope this helps. Good luck.

Dr. Clayton Greenway