While we enjoy our warm temperatures year-round here in Daytona Beach, so do insects—particularly mosquitoes—and these bloodsucking pests are notorious for transmitting a host of diseases. You need to know about heartworm disease  to help keep your pet safe from this deadly condition. Here are five key facts about heartworm disease every pet owner should know. 

#1: Heartworms are directly transmitted from mosquitoes to pets

Unlike other parasites, such as fleas, ticks, and intestinal worms, heartworms must go through a mosquito to infect a pet. The heartworm life cycle cannot advance to the infective stage that can affect your pet if the immature heartworms (i.e., microfilaria) do not develop inside the mosquito. So, if your dog has developed a heartworm infection, they cannot directly give heartworms to your cat. However, understand that if your pet is heartworm-positive, heartworms are a risk for your other pets, because the mosquitoes in your area carry this deadly parasite and can infect all pets. 

#2: Any mammal can contract heartworms, including indoor-only pets

While dogs and other canines are the preferred heartworm host, any mammal can fall victim to heartworms, including ferrets, sea lions, and people. Pets who are sheltered by living strictly indoors are also at risk for disease, since mosquitoes are extremely skilled at finding the smallest gap, crack, or hole to slip into your home and infect your indoor cat. Mosquitoes can infect pets who never venture so much as a whisker outdoors, so year-round heartworm prevention is crucial to keep all your furry pals safe from disease. 

#3: Heartworm disease signs vary between cats and dogs

Although cats and dogs can contract heartworms, the disease appears differently in each species. Since dogs are the preferred heartworm host, these deadly parasites can live for five to seven years in your pooch, reaching up to a foot in length. Heartworms take six months to reach adulthood, but the immature worms can wreak havoc in your pet’s body as soon as they are transmitted from a mosquito. Heartworm disease signs in dogs include:

  • Coughing
  • Exercise intolerance
  • Decreased appetite
  • Weight loss
  • Abdominal fluid accumulation
Severe heartworm cases can lead to caval syndrome, which is a blood flow blockage in the heart, marked by a sudden onset of labored breathing, pale gums, and dark, coffee-colored urine. Without prompt surgical removal of the heartworm blockage, few pets survive.

Cats with heartworm disease typically display respiratory signs in a condition known as heartworm associated respiratory disease (HARD), whose signs include:

  • Coughing
  • Asthma-like attacks
  • Periodic vomiting
  • Anorexia
  • Weight loss
  • Difficulty walking
  • Seizures
  • Fainting
  • Abdominal fluid accumulation
Unfortunately, one of the first feline heartworm disease signs can be sudden collapse, or sudden death.

#4: Heartworms are impossible to detect in pets without routine testing

Heartworms are parasites that reside in the blood vessels in and around your pet’s heart and lungs. Unlike some intestinal parasites that are shed via defecation, you cannot see heartworms in your pet, which is why routine testing is essential for detection. Many pets do not show heartworm disease signs until the condition is more advanced and irreparable damage has been done, but with annual testing, you can minimize your furry pal’s risk of circulatory system scarring. 

A heartworm infection can be difficult to diagnose, despite annual testing. False-negative test results are common for a variety of reasons, including:

  • The heartworms have not reached adulthood
  • All the adult heartworms are males
  • The adult heartworm load is too low to detect
For example, if a mosquito infected with microfilaria bit your dog four months ago, your pet will not test positive, despite carrying heartworms. Heartworm tests detect only the antigen from adult, female heartworms, which makes regular testing vital for diagnosis and prompt treatment to avoid permanent damage.

#5: Year-round prevention is the only way to keep your pet safe from heartworm disease

Since detection is challenging and the damage wrought by all heartworm life stages is significant and irreversible, year-round heartworm prevention is the only way to keep your furry friend safe from heartworm disease. Here in Daytona Beach, our temperatures never drop low enough to make a dent in the mosquito population, so your pet is always at risk for infection. Fortunately, a wide variety of heartworm preventives is available, including topical, oral, and injectable forms. No matter what preventive you choose, the key is remembering timely administration. Set a reminder on your phone, or mark the date on your calendar. With regular preventive administration and annual testing, together we can ensure your pet remains safe and protected from life-threatening heartworm disease. 

Unsure which heartworm preventive will work best for your pet? Or, is your furry pal due for their annual heartworm test to ensure they are negative? Call your Driftwood Animal Hospital team to schedule an appointment for a heartworm test and to discuss your pet’s prevention options.