You are right that some dogs will never develop heartworms. Some will never develop heartworms even if they don’t take preventive medication. But that doesn’t mean the potential does not exist for infection. And it also doesn’t relieve my colleagues and I, as veterinarians, of the responsibility of advising our clients of this fact.

I’ve been practicing veterinary medicine for well over 20 years now and the recommendation during that time period has always been to test annually for heartworms. So, this is not a new recommendation. In my professional opinion, performing only one heartworm test over a dog’s entire lifetime has never been “good enough”. Testing annually for heartworms is a preventive procedure that is recommended because of the fact that heartworms can cause major damage to a dog’s organ systems. This damage can occur before clinical signs appear and treatment is much more likely to be successful if infection is detected in the early stages, before clinical signs appear. It’s not all that different than regularly testing blood pressure for a human patient that is taking blood pressure medication, for example. You test the blood pressure to make sure the medication is doing it’s job. No doctor would ever think of starting a patient on blood pressure medication without ever testing the patient’s blood pressure again, even knowing the patient is religiously taking the medication. Heartworm medications are quite effective in most situations to the best of our knowledge. But no medication is 100% effective. And recently, concerns have been raised about heartworm resistance to heartworm preventive medications in certain areas of the country. So, annual testing is just a safeguard to keep your dog as healthy as possible.

In all honesty, Patrice, heartworm testing is not a huge profit center, at least not in my practice. We don’t charge that much more than what it costs us to do the test for our patients. If I really wanted to “rake in more money”, I could do that easily by not recommending heartworm testing or prevention and then treating the heartworm positive dogs that come to me. Believe me, that would be much more profitable. But, it’s not about the money. It’s about what’s best for the pet.

I’m interested in hearing about your experiences with the manufacturers of heartworm preventive medicines. I personally have never had problems with them not honoring their obligations relating to the guarantee. Admittedly, I’ve only had the situation arise a handful of times (thankfully) and usually in regards to intestinal parasite claims and not heartworm claims. In those rare instances, the manufacturers were quite concerned and helpful and they paid the fees as promised. If you have had other experiences, please do share them with us. I’d love to hear about them and it would be valuable to pass this type of information along to other readers as well.

Thank you, Patrice, for taking the time to share your opinions. I appreciate that you have addressed some important points that many pet owners worry about.

Simply want to say your article is awesome. The clarity in your post is simply impressive and I can take for granted you are an expert on this field….