Should You Give Your Dog Heartworm Preventative in the Winter?


Are you giving your dog heartworm preventative during the winter months?  We all probably know that mosquito bites transmit heartworms and there are no mosquitos here in the winter.  So it should be okay, right?   Well, turns out – maybe not.

I got to thinking that I think I know all about heartworms and how they are transmitted, but do I really know all I need to know?  I’ve talked before about my vet’s Wellness Plan that I have for my two girls.  Heartguard is included in the plan so I have used it all year since it’s free – ok, not really free, but you know what I mean. 

A large percentage rescued dogs in the South will have heartworms.  We see a lot of this at the shelter whether they are coming from a county animal control or from an owner who is surrendering the pet.  Once the dog is treated for the heartworms and goes through the 30 day recovery, they are usually fine.   But this doesn’t mean they can’t get heartworms again.  Every mosquito is a potential carrier to every dog. 

I got busy on the internet and found some pretty interesting reasons why it is important to continue heartworm preventative all year long in the southern US where we have a lot of mosquitos.   There is a ton of complicated information out there.  Here are a couple of things I learned.

-          It’s easy to forget or be really late with the medication for one or two months.  Or maybe we just don’t have the money at some point.  It’s pretty expensive, particularly if you have more than one dog.  Now if you use it year-round and you miss a month, your dog will probably still be protected.  Using the preventative 12 months a year allows the medication to build up in your dog’s system and that may absorb missing a month.

-          Once the cycle gets started, it can get out of control really fast.  From the mosquito bite, to the tiny little worm stage moving from under the skin to the blood stream takes about 60 days.  Another 6 to 7 months and the worms are at adult stage.  Then the game is on and heartworm treatment is really expensive.  

Bottom line, owning a dog is a responsibility.  If you live in the South, you will be taking a chance not using heartworm preventative all year long.   What do you think?  Worth the chance?