Heartworm disease is a serious and dangerous illness that affects dogs and cats. It is caused by worms that live in the heart, lungs, and blood vessels and are spread by mosquito bites. Adult heartworms are not microscopic worms- they resemble spaghetti, can be over twelve inches long, and live in the heart, lungs, and blood vessels. A dog can be infected with several hundred worms at a time. Heartworms are present in all 50 states, and we see positive pets here at Friendship.
Heartworms can infect many species, such as dogs, cats, ferrets, coyotes, wolves, foxes, and occasionally, humans. A mosquito bites an infected animal and picks up baby heartworms, and over the next 10-14 days, those babies mature into an infective stage in the mosquito. When the mosquito bites the next susceptible animal, that animal will be exposed to heartworms. It takes 6 months from the time the animal is infected before they will test positive for heartworms.
Heartworms can live up to 7 years in dogs and 3 years in cats. That entire time, they are causing damage to your pet. A pet can be re-exposed to heartworms repeatedly. Having heartworms or having had heartworms does not protect a pet from being reinfected. Heartworm disease can cause severe health problems or even death if not treated.
The good news? Heartworm disease in our pets is preventable! Let’s talk about how to keep your pets safe.
Heartworm Disease in Dogs
What Are the Signs of Heartworm Disease?
Dogs with heartworms may not show signs at first. But as the disease gets worse, they might:
- Cough and wheeze
- Tire easily after playing or walking
- Have reduced appetite
- Lose weight
- Have a swollen belly (from fluid buildup due to heart failure)
In really bad cases, heartworms can block blood flow. This is called caval syndrome, and it can be deadly.
How Can You Prevent Heartworm Disease?
It’s much easier to prevent heartworms than to treat them! There are many options for the prevention of heartworm disease, including pills, chews, topicals, and an injection that lasts several months.
We also recommend a yearly heartworm test to make sure your dog is safe. Even if you give prevention, testing is important! No prevention is 100% effective. Because it takes 6 months after a pet is infected for them to test positive, a puppy over 7 months or an adult dog that has not been on heartworm prevention needs a test before starting heartworm prevention, then another test in 6 months.
Here in the Carolinas, mosquitoes are active year-round, so prevention should be given 12 months a year. Mosquitoes get into homes, so even indoor pets should be on prevention.
How Is Heartworm Disease Treated?
If your dog has a positive test, your veterinarian will likely run an additional test to confirm the infection. Treatment for heartworms is expensive and can be challenging for you and your dog. Your dog will need blood work and x-rays before a series of injections are given over weeks to kill the worms. During treatment, your dog must have strict exercise restrictions and additional medications given at home to prevent complications. The earlier a heartworm infection is treated, the better chances your dog has for a full recovery.
Heartworm Disease in Cats
While heartworm disease is more common in dogs, cats can also get heartworms. Most heartworms in cats don’t grow into adults, but even immature worms can cause damage to a cat’s heart and lungs. It is harder to detect heartworms in cats, and may require blood testing, x-rays, and an ultrasound.
Signs of Heartworm Disease in Cats
Cats with heartworms may:
- Cough or wheeze
- Vomiting
- Feeling lethargic or weak
- Suddenly collapse (in very serious cases) or death
How to Protect Cats from Heartworms
There is no cure for heartworm disease in cats, so prevention is extra important! Monthly heartworm prevention medicine (in oral or topical form) is the only way to keep cats safe.
How to Keep Your Pets Safe
✔ Give heartworm prevention medicine every month (even in winter!)
✔ Get yearly heartworm tests for dogs
✔ Protect both indoor and outdoor pets—mosquitoes can sneak inside!
Heartworm disease is dangerous but preventable. If you have questions about how to protect your pet, call Friendship Animal Hospital today at 704-889-7387!
