Why Heartworm Prevention Is Needed All Year

Mosquitoes carry an awful parasite called heartworms.  Just like the name implies, heartworms are worms that live in the hearts of dogs and cats.  They can be deadly.

Heartworms are serious, but why do we recommend prevention all year?  Good question.  If there are no mosquitoes out right now, my pet doesn’t need protection, right?  Unfortunately, no.

The mosquito bites your pet (let’s call her Coco) and if the mosquito has baby heartworms, it transfers them to Coco.  It takes about six months for those baby heartworms to travel to the bloodstream. At this point, you give Coco her monthly preventive (gold star for you!) and those baby heartworms die.  If you did not give the preventive (oops!), then those babies make their way to Coco’s heart and grow up to become adults that can’t be killed by preventives.  So think about it.  The prevention you gave today is killing baby heartworms from a bite six months ago.  Maybe it’s cold now, but six months ago it was warmer and there were still mosquitoes around.

As we all know, our Indiana weather is pretty unpredictable, so it’s tough to tell when mosquito season starts and ends.  Even if we did, knowing the heartworms’ life cycle convinces us to recommend prevention all year round.