Heartworm discussion

Happy Fall!

I realize this isn’t the typical time of year to discuss heartworm prevention, but maybe it should be. As recently as five years ago, we were still on track to see and treat about one case of canine heartworm disease (HWD) every three years. Fast forward to last year and we treated four cases at Beach Animal Hospital, including my daughter’s rescue pup, Bennie.

We knew he was positive when we adopted him, but she fell hard for him and the rescue gave us a “great deal” on him. While I have great faith in the preventatives, I’d be lying if I didn’t come clean and admit I was a little nervous having a heartworm positive dog around my four dogs and cat in July and August. Yes, cats can get HWD too. More on that later.

Last week we finished treatment on our fourth heartworm positive dog of 2023 and it is only September! I hope we are done for the year, but we still have three months to go. Why the uptick in cases? The reason seems to be threefold.

First, we get a lot of rescue dogs coming into our area from places where HWD is more endemic. This is great for the dogs, but unfortunately some of them are bringing HWD with them. They are usually tested before heading up here but one negative test doesn’t guarantee they stay negative. And some dogs are transported while being treated. That means we have to be extra diligent to do our part to prevent spread of the disease.

The second reason for the increase in cases lately is that some preventatives are being used for the “slow kill” method of treatment. This method is less than ideal but also less costly. There are some downsides to this method including that it is believed to contribute to resistance in some of our preventive choices. Resistance renders the medication less effective.

Lastly, traditionally July and August were considered peak months for HW transmission. Heartworm disease is spread when a mosquito bites an infected dog and then passes it along by biting another dog. Climate change is likely extending our “heartworm season” by several months. As mentioned earlier, unfortunately cats are not off the hook when it comes to HWD. While they get a different clinical syndrome than dogs, the testing is less straightforward and there is no definitive treatment. The summer Bennie lived with us during his treatment, I put my indoor cat, Charlie, on a preventative. We have a few available preventatives for cats and we strongly recommend them for our outdoor kitty patients.

So maybe September isn’t the wrong time of year to talk about HWD. Doctors Yeaw, Siddons, Toll, and I all strongly recommend that all dogs be on heartworm prevention year round. We have several choices and are happy to have a discussion about which is the best choice for your good boy or girl. We also recommend testing at least every two years. We usually have the results for you before you leave the office.

How did things turn out for Bennie? He is heartworm free and his period of post treatment exercise restriction has ended. I am happy to report that the country dog from West Virginia is living his best life on the city streets of Washington DC with his best pal.