6 Reasons to Take Heartworm Prevention Seriously

Pet Health and Safety  •  Pam Karkow  •  Tuesday, October 5, 2021

We had no idea how we’d keep the big guy still for a whole month.

When my neighbor’s newly adopted dog was diagnosed with heartworms, they were told that to treat the disease, he'd need an injection followed by 30 days of rest, then two more injections. The first week after the injection it is important that the dog not get excited, race around, or engage in any type of exercise. 

A rescue, Dempsey was a very large, muscular boxer who had no idea of his size. He frolicked and played in the yard like a puppy and was the biggest lapdog you’ve ever seen. The idea of him being still and calm was laughable. My friends ended up crating him most of the time during that initial month, as the injections were given and the heartworms died and were reabsorbed by his body. Dempsey came through the ordeal just fine, but not without a lot of worrying from his parents and human brothers.  

April is Heartworm Awareness Month and springtime is when we start seeing evidence of mosquitoes so it is the opportune time to discuss reasons we should take heartworm prevention seriously.

  1. Heartworms are transmitted by mosquitoes. When an infected mosquito bites your pet, larval heartworms, called microfilaria, enter his/her body. For about seven months, these larvae mature into adult heartworms, often without any signs or symptoms in your dog or cat. The adult heartworms lodge in the heart, lungs, and surrounding blood vessels and begin reproducing. It only takes one mosquito bite, and your dog could end up with 250 worms in his or her system!
  2. The disease has been reported in all 50 states. According to Sheldon Rubin, the 2007-2010 president of the American Heartworm Society, “if you have mosquitoes and you have animals, you’re going to have heartworms. It’s just that simple.” And even if your pet has had heartworms and survived, he/she can get them again. 
  3. The best defense is a good offense.  It is important to use prevention year-round, even in the cooler months when mosquitoes are not as prevalent. Some heartworm preventatives also protect against hookworm, roundworm, fleas, and tapeworms which your pet is susceptible to year-round. It can also be difficult to remember to give medication regularly if only given certain months. Year-round care is easier to manage.
  4. After being bitten by an infected mosquito, your dog could have as many as 250 worms in his system!  Better to safeguard against an infestation than try to treat it when it happens.  There is a wide range of options available for prevention. My dog thinks she is getting a treat the first of every month when I give her the meat-flavored chewable heartworm pill. Afraid you’ll forget? You might opt for an injection that will cover your dog for 12 months. Talk to your vet about the best heartworm prevention for your dog.
  5. Treatment for heartworm disease is often costly and risky. As I shared in my personal story above, no one wants to go through the difficulty of keeping a pet in the crate as the medicine does its work and the heartworms die. Some dogs, especially ones who are heavily infected, may even develop a cough for seven to eight weeks after treatment. Treatment is not guaranteed to work, and some dogs can experience lasting damage to their heart as a result of heartworm disease.
  6. Many pet insurance companies will cover part of the cost of heartworm preventatives.  Prevention is as easy as a pill or an injection. The best line of defense is a routine prevention protocol. PetPartners can help you rest easy with their Defender and DefenderPlus plans. These plans provide reimbursement separately for heartworm prevention and flea/tick prevention.


The idea of my dog having worms is terrifying! Prevention is such an easy step to add to our routine, especially when it is a yummy step. April is a great month to educate yourself on the reality of heartworm disease and to make sure you are protecting your furry loved ones.

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