Heartworm disease might sound like something distant or uncommon—but the truth is that this parasite begins its deadly journey with a simple mosquito bite. Once inside your pet’s body, heartworms grow silently, often unnoticed until serious damage is already done. At Burien Veterinary Hospital, we believe knowledge is a powerful tool. When you understand how heartworms live, spread, and harm, you’re better equipped to protect your pet for life.
The lifecycle of a heartworm starts when a mosquito bites an infected animal and picks up microscopic larvae called microfilariae. These larvae develop inside the mosquito for about 10–14 days, transforming into the infective stage. When that mosquito bites another animal—like your dog or cat—it transfers the larvae through the skin and into the bloodstream. And just like that, your pet is now a host to a potentially life-threatening parasite.
Once inside your pet, the larvae begin a months-long journey through the bloodstream. Eventually, they reach the lungs and heart, where they continue maturing into adult heartworms—sometimes up to 12 inches long. Because of how slowly heartworm disease progresses, most pets don’t show signs of illness until significant internal damage has already occurred.
In dogs, heartworms can live up to seven years, causing chronic inflammation, restricted blood flow, and heart failure if untreated.
In cats, the worms may not survive as long, but even a few can cause severe respiratory issues and even sudden death.
As heartworms mature and reproduce, they create a growing population of parasites in your pet’s body. The impact over time can include:
These effects are serious and often irreversible. Early heartworm disease intervention and prevention are very important to your pet’s health.
When you see how heartworms develop step-by-step—from one mosquito bite to an infestation in the heart—it becomes clear why parasite prevention is essential. Heartworm disease is 100% preventable. This disease is a real threat that can be managed with just a few simple habits.
Preventative medications kill immature larvae before they reach the heart and lungs. Timing and consistency matter. Veterinarians recommend monthly heartworm preventatives (oral or topical) alongside routine heartworm testing. There are also annual or bi-annual heartworm injection options for dogs who prefer less frequent dosing. Prevention is much more affordable, comfortable, and safe than treatment—and it spares your pet from the suffering heartworms can cause.
The more you know about how heartworm disease works, the easier it is to prevent. By committing to year-round prevention and regular testing with Burien Veterinary Hospital, you can stop this silent killer in its tracks. We want to make heartworm disease prevention easy and stress-free. Ready to protect your pet from the inside out? Are you a pet owner in Burien, White Center, Tukwila, or a neighboring community? Book an appointment for a heartworm test or heartworm prevention today.
