Your Pet Needs Preventive Care Just Like You Do

If there are two words that should not be connected, it’s heart and worm. The disease is as it sounds: worms living in the heart and surrounding blood vessels of affected pets.

Heartworm is a potentially fatal infection caused by parasitic worms transmitted via mosquitoes. In 2016, of the more than 2.5 million dogs seen at Banfield Pet Hospitals across the country, 1 in 174 tested were diagnosed with heartworm disease – a staggering and concerning statistic.

Banfield veterinarians Dr. Jovanna Radillo in Carmichael, CA, Dr. Andrea Sanchez in Vancouver, WA and Dr. Maria Ramirez-Gorton in Newport News, VA, shared insights about the disease, treatment and prevention. The takeaway: year-round heartworm prevention is paramount against protecting pets from this disease, which can prove life-threatening.

“Heartworm disease is really scary,” said Dr. Ramirez-Gorton. “But it’s so easy and relatively inexpensive to prevent.”

Banfield recommends heartworm tests annually, as well as preventive medication determined in partnership with your veterinarian. Options include a monthly pill or topical at home, or an injection every six months at your veterinarian’s office. The key is remaining diligent and consistent throughout the year. If you keep pets on heartworm prevention all year long, the possibility of contracting the disease is almost zero. If you miss even one month, that can prove dangerous to your pets, especially in high-risk states with warm, humid climates. 

What happens?

According to the American Heartworm Society, heartworm disease is caused by foot-long worms that live in the heart, lungs and associated blood vessels of affected pets, causing severe lung disease, heart failure and damage to other organs in the body. You’ll find heartworms wherever you find mosquitos – the insects transmit heartworms from infected animals to other pets. According to Dr. Sanchez, “One bite from an infected mosquito is all it takes for your pet to become infected with heartworm.” 

Unfortunately, there are different stages of the illness, so it can be very difficult to know your pet is infected without testing – and it’s important to know that many pets infected with heartworm show no signs of the disease but can act as a source of infection for other pets.

Signs of heartworm infection in dogs may include coughing, fatigue, weight loss, excessive panting or difficulty breathing, which Dr. Sanchez says are most often associated with heart failure. Heartworm disease in cats is most often associated with asthma-type symptoms and sudden death. 

Treatment options

There is currently no heartworm treatment available for cats. If a dog tests positive for heartworm disease, they will need to undergo treatment to help minimize the damage the worms cause, which Dr. Radillo tells us is very taxing on their body, not to mention lengthy and expensive.

Additionally, heartworms will almost always cause permanent damage, even with treatment, so prevention is always the recommended and preferred route. 

What areas of the country are affected?

Although cases of this potentially fatal disease have been recorded in all 50 states, Banfield’s State of Pet Health Report suggests heartworm disease is most prevalent throughout the southeastern United States, likely due to the generally humid climate, which may give mosquitos more standing water in which to breed.

Dr. Sanchez adds, “Heartworm remains on the rise in the U.S., in part due to last year’s extreme hurricane season that caused flooding across the Gulf coast, eastern seaboard and Puerto Rico.” Given the disease exists in all 50 states, veterinarians recommend pet owners assume their pets are at risk anywhere and take preventive measures – even for indoor pets and those that have never left their home state.

Unfortunately, veterinarians diagnose pets with heartworm disease daily, including Dr. Radillo who recently experienced a new client was surprised to learn her dog had contracted heartworm disease before moving to California from the South. The client hadn’t realized the risk and severity, so had previously decided against preventive measures to save a little money. Thanks to education, this client – like many others Dr. Radillo partners with – now realizes the danger and wants to do everything she can to treat and prevent heartworm for her pet.

“All pet parents should know what’s at stake. It’s a few extra dollars a month, but a lifetime of prevention is a much safer bet than waiting for them to get infected,” said Dr. Radillo. “And more than money: it’s in your pet’s best interest.” 

For more information on heartworm, talk to your veterinarian about the right preventive medication for your pet, and visit or To find a Banfield Pet Hospital near you, visit