Heartworm Transmission and Prevention in Your Pet

Heartworm disease is potentially deadly for your pet, and should not be taken lightly. Although heartworm transmission, life cycle, and prevention can be confusing, protecting your pet is simple. 

How is heartworm disease transmitted?

It takes the bite of only one infected mosquito to put your pet at risk for developing heartworm disease. Once an infected mosquito has bitten your pet, heartworm larvae invade her bloodstream, traveling to the vessels surrounding the heart and lungs. Heartworms develop slowly, and can take six to nine months to reach adulthood. 

Fortunately, pets cannot transmit heartworms directly to each other—only mosquitoes can transmit heartworm larvae from animal to animal. After a mosquito takes a blood meal from an infected animal, the immature heartworms develop into infective larvae, which enter their new host when the mosquito bites its victim.

Heartworm disease may not be transmitted directly from pet to pet, but a positive heartworm diagnosis in your area means that the parasite has infected your mosquito population and can also infect your pet.

Can cats get heartworm disease?

Both cats and dogs can become infected with heartworm disease, but cats are not a natural host for heartworms, so the parasite cannot reproduce inside a cat. But, heartworms can still wreak havoc on a cat’s cardiovascular system, causing serious illness and potentially even sudden collapse and death. Even indoor-only cats are susceptible to the disease, because mosquitoes can easily slip in through open doors and window-screen holes. Cats infected with heartworms show different disease signs than dogs, and usually experience respiratory-related signs similar to asthma. 

How can I prevent heartworm disease in my cat?

Because there is no approved heartworm treatment for cats, prevention is important. There are safe, reliable heartworm preventive medications designed for cats, and our veterinary team can help you determine the best preventive option for your feline friend. 

Can dogs get heartworm disease?

Dogs are a natural host for heartworms, so, once a dog is infected, the worms will grow, mature, and reproduce inside the dog. Some dogs have had up to 300 of the spaghetti-like worms near the heart, lungs, and surrounding blood vessels. Dogs with heartworm disease may exhibit a mild cough, reluctance to exercise, fatigue after activity, decreased appetite, or weight loss.

How can I prevent heartworm disease in my dog?

Once a dog becomes infected with heartworm disease, treatment is difficult and costly. Many dogs never fully recover from a heartworm infection, and some may even die as a result of the treatment. Fortunately, heartworms can be prevented in dogs. There are a variety of preventive medications, from monthly oral and topical products, to yearly injectables. If administering monthly preventives to your dog is a struggle, consider switching to ProHeart 12, an annual injectable preventive. ProHeart 12’s active ingredient is contained in slow-dissolving microspheres stored in your dog’s fat-storing connective tissue. Throughout the year, the medicine is evenly released, keeping your dog heartworm-free. At the time of injection, ProHeart 12 also kills larval and adult hookworms. 

ProHeart 12:

  • Can be used in reproducing dogs and their puppies
  • Can be used in collies sensitive to ivermectin, a common monthly heartworm-preventive ingredient
  • Is safe for healthy dogs over 12 months of age
  • Can be given in our office during your dog’s annual wellness visit
  • Won’t be vomited or spit out, which can happen with some traditional oral heartworm preventives
  • Gives you peace of mind, knowing your dog won’t miss a dose of heartworm prevention

Is heartworm prevention necessary during the winter?

Our Massachusetts winters aren’t the most predictable. Mosquitoes—and fleas and ticks—are hardy pests, and can spring forth when the weather warms up to 35 degrees or higher. At least one winter day will likely be warm enough for parasites to emerge, and you put your pet at risk for contracting devastating heartworm disease if you skip only one monthly preventive dose.  

Are you interested in switching your dog to ProHeart 12? Or, does your cat need heartworm preventive to stay safe? Give us a call to discuss your pet’s heartworm-prevention options.