Heartworms

Today, I’d like to talk about a scary (and downright disgusting) parasite that used to be rare around here but has unfortunately become endemic—HEARTWORMS.

Heartworm disease is caused by actual worms that migrate to the heart and can lead to congestive heart failure, anaphylactic shock, and even death. These parasites are transmitted by mosquito bites, which means any dog or cat can get heartworms. I’ve even diagnosed a strictly indoor dog—pee pad trained, never left the house except for vet visits—with heartworm disease. It doesn’t matter if your pet is indoor-only, goes on short walks, lives in a gated community, or never interacts with other animals—your pet is at risk.

In 2005, Hurricane Katrina led to the rehoming of many pets from the South, some of which were heartworm-positive. This contributed to the infection of local wildlife, especially coyotes. Now, heartworm is considered endemic to our area, and unfortunately, there’s no way to fully eliminate it. Mosquitoes are the vector—and whenever temperatures rise above 40°F for 24 hours, mosquitoes become active and start spreading heartworms. Due to milder winters, we no longer have a true “off-season” here in Cincinnati, Ohio. In fact, we are now considered the heartworm capital of the United States.

It only takes one bite from an infected mosquito to transmit heartworm. It takes about six months for the worms to mature in the heart. The 4DX test, which we recommend annually at County Animal Hospital, detects adult worms—but there is a period of time when heartworms are present but undetectable. That’s why year-round prevention is critical. Most infected pets show no early signs, and by the time symptoms appear, the disease is often severe and potentially fatal.

We recommend year-round heartworm prevention and annual heartworm testing. There are several options available, including monthly pills, monthly topicals, and the ProHeart 12-month injection (think of it like a heartworm vaccine). Some options also protect against fleas, ticks, and intestinal parasites. Talk to your veterinarian to determine the best fit for your pet’s needs and lifestyle.

If your dog tests positive for heartworm, a treatment plan is available and follows the guidelines set by the American Heartworm Society. However, treatment is expensive, lengthy, and not without risk—which is why prevention is the best approach. Unfortunately, for cats, there is no standard treatment. In some cases, a veterinary cardiologist may attempt surgical removal, but this is rare and not widely accessible.

If your dog or cat is not currently on heartworm prevention, please call our office to schedule a consultation. Preventing this potentially fatal disease is simple and effective—and a critical step toward your pet’s long, healthy life. I look forward to helping you protect your furry family members.