Heartworm disease cases in dogs are on the rise this year in Dutchess County. According to the Companion Animal Parasite Council, about 1 of every 157 dogs tested is positive for heartworm disease, compared with 1 of 205 dogs tested in 2018. With the variety of convenient heartworm preventives available, why are more pets contracting this potentially life-threatening disease?

What is heartworm disease?

Heartworms are parasites that live in the heart, lungs, and nearby blood vessels of mammals. Dogs are the most common hosts. Although rare, people can also contract heartworm disease. Mosquitoes transmit heartworm disease when they bite an infected animal and then pass along the infective larvae, called microfilaria, to the next victim they bite.  

Adult heartworms, which can grow up to a foot in length, can number in the hundreds and live for 5 to 7 years. At least 60% of infective larvae reach adulthood without incidence, continuously adding to the parasite load. Without treatment, the worms can permanently damage the heart, lungs, and arteries, so early detection is critical.

Adult heartworm infection is rare in cats, because they are not the preferred host. Usually only one or two heartworms reach maturity in cats, and those adults have a shorter lifespan of 2 or 3 years. Since so few (less than 10%) heartworms in cats reach adulthood, the limitations of common heartworm testing make detection difficult. However, even immature heartworms can severely damage your cat.

Is my pet at risk for heartworm disease?

Every pet is at risk for contracting heartworm disease. This deadly disease has been found in all 50 U.S. states, proving no pet is safe from mosquitoes. The American Heartworm Society recommends year-round heartworm prevention for all pets, regardless of lifestyle or climate.

What signs will my pet show if she becomes infected with heartworm disease?

Signs of heartworm disease can be different in dogs and cats. Cats often display more respiratory issues, a condition known as heartworm-associated respiratory disease (HARD). As the microfilariae migrate through the cat’s blood vessels, heart, and lungs, they trigger a severe inflammatory response. Signs of HARD in cats include:

  • Coughing
  • Difficulty breathing
  • Asthma-like attacks
  • Lethargy
  • Decreased appetite
  • Vomiting
  • Diarrhea
  • Rapid heart rate
  • Weight loss
  • Blindness
  • Collapse
  • Sudden death

Adult heartworms cause many clinical signs in dogs, and symptoms progress to more severe stages as the worm burden increases. If your dog has heartworm disease, you may notice:

  • Coughing
  • Reluctance to play
  • Inability to exercise for an extended period
  • Rapid or difficulty breathing
  • Decreased appetite
  • Weight loss
  • A swollen abdomen due to fluid buildup from heart failure

Pets may not exhibit heartworm disease signs for several months or even years. Traditional testing requires at least six months from time of transmission to a positive test result, due to the heartworm life cycle. Annual testing is critical so heartworm disease is diagnosed early enough to prevent its progression.

How can I protect my pet from heartworm disease?

There is a wide variety of heartworm preventives available, and some can protect dogs and cats from additional parasites. Since no approved treatment for heartworm disease is available for cats, the only way to keep your cat safe from this destructive condition is prevention. Cats are not known for cooperating when being medicated, but many options, including topical heartworm preventives, are available.

Need help finding the perfect heartworm preventive for your pet? Stop by our hospital for assistance in choosing the best product for your furry friend.