As the weather gets warmer, people are more active outdoors…and, so are insects. Everyone notices the flies and mosquitoes buzzing around while they are outside having fun, and most people will protect themselves with bug spray to lower the chance of mosquito bites. Meanwhile, pets are being bitten by those same mosquitoes and could be exposed to heartworm disease if they are not protected.   

What is heartworm disease?

Potentially fatal, heartworm disease infects pets worldwide. It is caused by heartworms that reside in the pet’s heart, lungs, and blood vessels. If left untreated, heartworms can cause lung disease and the failure of multiple organs, including the heart. Heartworm disease is common in dogs, as they are the natural host for the disease, but cats, ferrets, wolves, coyotes, foxes, and even humans can become infected, too, although infection in humans is rare.

How is heartworm disease transmitted?

Mosquitoes transmit heartworm disease when they bite an animal already infected with heartworms and then pass the parasite onto the next animal it bites. The mosquito first ingests the microscopic heartworm circulating in the infected animal’s bloodstream. The heartworms develop into larvae over the next 10 to 14 days and then will be deposited in the bloodstream of the mosquito’s next victim.

The heartworm larvae will take the next six months to grow into mature adult heartworms that can be as long as 12 inches and resemble spaghetti noodles. Adult heartworms can live for five to seven years in dogs and two to three years in cats.  

What does heartworm disease look like in dogs?

Heartworm disease can be difficult to detect in the early stages. Your dog may not exhibit any signs at first, but then may develop a mild cough. As the disease progresses, your dog may experience:

  • Difficulty breathing
  • Decreased appetite
  • Weight loss
  • Exhaustion after exercise

In the later disease stages, mature worms may block blood flow, which could lead to heart failure or other serious, life-threatening complications.

Can heartworm disease be treated in dogs?

Treatment is available for dogs who test positive for heartworm disease. Depending on the severity of your dog’s condition, your veterinarian may need to stabilize her before developing a treatment plan that best suits her needs.

Can heartworm disease be prevented in dogs?

Several monthly heartworm-preventive options are available. Your veterinarian can help choose the best heartworm preventive for you and your pet, who will need to be tested to ensure she does not have heartworm disease.

What does heartworm disease look like in cats?

Cats can contract heartworm disease, but they are not a natural host of the disease, and they do not show the same signs as dogs. Cats usually harbor only a few heartworms in their system and show no signs of infection. Sometimes a cat can remedy the infestation without treatment, but cats who don’t may exhibit vomiting, diarrhea, loss of appetite, weight loss, or sudden death.   

Can heartworm disease be treated in cats?

No medication has been approved to safely treat heartworm disease in cats, but your veterinarian can provide care and create a long-term plan to manage your cat’s symptoms if she is diagnosed with the disease.

Can heartworm disease be prevented in cats?

Monthly preventives that are safe for cats are available in topical and pill forms. Our veterinary health care team can prescribe a heartworm preventive for your cat after she has tested negative for the disease.

Is your pet on a regular heartworm preventive? Contact us so we can help you prevent heartworm infection in your dog or cat.