How Heartworm Testing Works: What Pet Owners Need to Know

With mosquito season in full swing, it’s more important than ever to make sure your pet doesn’t have heartworm disease. Heartworm prevention medication is the best way to keep the worms from making a home in your pet’s body. 

But before you start heartworm treatment, your veterinarian will want to make sure your pet doesn’t already have heartworms. This is because while heartworm medication kills heartworm larvae, it doesn’t kill adult heartworms. 

A round of heartworm testing can tell your veterinary team whether your pup or kitty needs preventive medication or active treatment. 

Here’s what the team at Bowman Veterinary Hospital wants you to know about how heartworm testing works. 

Heartworm Testing 101 

Avoiding heartworm prevention carries serious risks, including the potential for devastating illness and even death. But before we can explore how heartworm testing works, we have to understand how the parasite infects our pets. 

How do Heartworms Infect Pets?

When a heartworm-carrying mosquito bites your pet, it deposits infective heartworm larvae into your dog or cat’s bloodstream. Dogs are a definitive host for heartworms. This means these pesky parasites can live out an entire lifecycle within your canine’s body—mainly within the heart and lungs. 

Heartworm prevention medication works by killing the larvae before they mature into adulthood. But the medication only works if your pet receives it within 50 days of a bite. After this time, heartworms molt into their juvenile stage—and preventive meds won’t get rid of them. 

Within six to seven months, the larvae become fully mature adults. They mate with each other and produce more offspring, multiplying the number of heartworms in your dog. By this point, your dog will need aggressive treatment to get rid of the parasites. 

Cats are atypical hosts for heartworms, so the parasite can’t reach adulthood after infecting your kitty. But even a few heartworms can negatively affect your feline friend and cause heartworm associated respiratory disease (HARD). Medications to treat heartworm in dogs don’t work in cats. Because of this, prevention is essential. 

Prevention can only begin after a round of heartworm tests. 

The Ins and Outs of Heartworm Testing

There are two heartworm tests for dogs. One detects heartworm larvae and the other can pick up the presence of adult heartworms. Here’s how they work:

• Heartworm Larvae Test: A veterinarian takes a sample of your dog’s blood and runs it through a centrifuge to concentrate the larvae. Or, they run the sample through an ultra-fine filter. With a microscope, the team can tell whether heartworm larvae are present in the blood sample.
• Heartworm Adult Test: Your veterinary team performs a heartworm antigen test on a blood sample from your dog. This test can detect the presence of adult female heartworms.

All dogs aged seven months or older should receive both tests every year.

Identifying heartworms is harder in cats because the parasite doesn’t live to adulthood. Your veterinary team may need to use blood tests along with X-rays or ultrasounds to detect the presence of heartworms. 

At Bowman Veterinary Hospital, our skilled veterinarians can help prevent, diagnose, and treat heartworm in your pawsome pals. Early detection is crucial to a good outcome. If you think your dog or cat may be infected or you need to start your pet on a preventive, call us at 530- 823‑6306.