As animal owners, we know that heartworm should be avoided at all costs. But do we really know why?

From information about transmission and life cycles to the importance of protecting your animal, this guide to all things heartworm will equip you with the necessary information to understand the risks and make informed decisions.

What Is Heartworm?

Heartworm is a parasitic roundworm that tends to primarily choose canines as its host. Despite its name, adult parasites tend to take up residence in the animal’s pulmonary system as well as the heart, causing serious damage to the surrounding tissues. An adult worm typically measures between 6 and 12 inches.

How Is Heartworm Transmitted?

Heartworm is transmitted via mosquito bite. It’s the only way for a dog to be infected. It cannot be transmitted through contact with an infected animal. The life cycle begins when a mosquito picks up a microfilarie (heartworm larvae) from the blood of an infected animal. It then serves as a host, allowing the microfilarie to mature. The larvae is then passed on to your dog via mosquito bite, where it takes 50 to 70 days to mature. At this point, the adult worm takes up residence in the host’s heart or lungs. Within 30 days, the worms reach sexual maturity and in turn release more microfilarie, thus completing the cycle.

Is Heartworm Fatal?

Left untreated, yes. Serious heartworm infections wreak havoc on an animal’s body and cause serious illness. Usually, untreated animals die of congestive heart failure.

What Are The Symptoms of Heartworm?

At the onset, heartworm infection is typically asymptomatic. It can be virtually impossible to know whether a dog has been infected or not, especially given the fact that it’s difficult to detect mosquito bites through a dog’s coat. As the infection progresses, the dog typically develops a cough and becomes lethargic and unable to participate in physical activity.

How Is Heartworm Treated?

Because no treatment program currently exists that successfully eliminates both adult worms and larvae, the treatment of heartworm is a multi-step process. First, an arsenic compound is injected twice a day for two days. The purpose of this initial step is to kill the adult worms. The drug becomes effective within a week and takes a month or two to fully eliminate all of the adult worms. In order to ensure that the dead worms do not create blockages, dogs undergoing treatment for heartworms are basically stuck on bed rest.

Can Heartworm Be Prevented?

Because the risk of heartworm varies depending on location, climate, and other environmental factors, it is important to discuss preventative treatment options with your veterinarian. Heartworm prevention treatments are shown to stop 99% of potential infections.