Do you wonder why your veterinarian asks if your pet is up to date on their heartworm preventives at every appointment? Many pet owners underestimate their pet’s heartworm risk and the importance of year-round heartworm prevention. According to the American Heartworm Society, more than a million U.S. pets have heartworm—a serious and potentially fatal parasite transmitted by mosquitoes. Amid changing climates, that number continues to grow, yet this deadly condition is completely preventable, and the reason your veterinarian faithfully inquires about your pet’s heartworm preventives. April is National Heartworm Awareness Month, and our team at Walnut Creek Vet Hospital is sharing the facts to help you protect your pet. 

All pets are susceptible to heartworm disease

Heartworms have been diagnosed in pets in every state in the country. The parasites are transmitted when an infected mosquito bites your pet and the microscopic heartworm larvae (i.e., microfilariae) enter your pet’s body and reach the blood vessels surrounding the heart and lungs. During their six-month migration, the larvae mature into adults up to a foot long that reproduce, impacting the pet’s heart, lungs, and pulmonary blood vessels. While heartworms prefer canine hosts, any mammal, including cats and people, can contract heartworm disease. Indoor-only cats are also at risk, since mosquitoes can easily slip inside your home. 

Heartworm disease in pets can fly under the radar 

Heartworm disease can be challenging, because some pets show no signs, especially in the early stages, while signs in others gradually develop over months or years. Often, pet owners don’t realize their pet has the disease until they are tested for heartworms. Noticeable signs are more likely when the disease has advanced and may include:

  • Coughing, or difficulty breathing
  • Decreased appetite
  • Lethargy, fatigue, or unwillingness to exercise
  • Enlarged abdomen 
  • Collapse

Some cats can rid themselves of heartworms without showing any signs but, in some, the first disease sign is sudden death. Some common heartworm signs in cats include:

  • Coughing, difficulty breathing, or asthma attacks
  • Vomiting, lack of appetite, or weight loss
  • Collapse, or sudden death

Early detection improves your pet’s prognosis

Because heartworm disease is progressive, the earlier the detection and treatment, the better your pet’s prognosis. The American Heartworm Society recommends that pets be heartworm tested every 12 months and receive year-round heartworm prevention. Adult heartworms can be detected on a routine blood test, with a positive result confirmed with repeat testing, and then additional tests to look for immature worms and assess heart and lung function. Heartworm-infected cats do not always test positive, because only a few worms are present, which makes the additional tests necessary.

Treating heartworm is expensive and hard on pets

Although heartworm disease in dogs is treatable, the process is long, complex, painful—and expensive. And, despite treatment, many dogs suffer lifelong side effects because their heart muscle and large lung vessels are damaged. For a dog who has been tested and confirmed as heartworm disease-positive, a typical treatment plan includes:

  • Antibiotic therapy — Antibiotic therapy is generally instituted for approximately 60 days to reduce side effects and treat bacteria that the worms may carry.
  • Medications — Deep, painful injections of an arsenic-derived medication are administered to kill adult worms.
  • Exercise restriction — Dogs must be severely exercise-restricted to reduce the risk of potentially fatal exercise-induced side effects if the dying worms lodge in the lungs and cause a blockage.
  • Surgery — Surgical removal of the pet’s heavy worm burden may be an option in extreme cases.

Unfortunately, no safe treatment—only supportive care—is available for cats with heartworms, which makes prevention an absolute necessity. 

Protecting your pet from heartworm is easy 

Consistently administering year-round preventives is the easiest and most effective way to protect your pet from heartworm disease. Preventives, which are available in topical, oral, and injectable formulations to fit your pet’s lifestyle and medication acceptance, work by destroying the microfilariae before they mature into dangerous adult heartworms. We recommend that your pet be heartworm tested annually to confirm that the prevention is effective because rare breakthrough infections can occur. Heartworm testing is especially important if you have ever missed or forgotten your pet’s monthly preventive.

Heartworms significantly threaten your pet’s health, but you can easily protect them with proper preventive measures. Contact Walnut Creek Vet Hospital to schedule your pet’s next wellness visit, which will include a heartworm test, or for a heartworm prevention consultation, so your pet stays healthy and happyand heartworm-free.