Texas ranks among the top 10 states where heartworm disease is most prevalent. The disease can significantly damage your pet’s heart and lungs and result in a life-threatening situation. Our Memorial Villages Animal Hospital team is devoted to ensuring all pets maintain optimal health, and we explain what pet parents need to know about these harmful parasites.

Heartworm transmission to pets

Heartworms can affect dogs, cats, and many other mammals, but your pet won’t get the disease from an infected animal, because transmission requires a mosquito to act as an intermediate host. With 85 mosquito species identified in Texas, it’s no wonder that the disease is prevalent in the Lone Star state.

Dogs and wild canids, such as coyotes, are natural mosquito hosts, which means the parasites can mature and breed while parasitizing these animals. When the heartworms breed in a natural host, they produce baby heartworms (i.e., microfilariae) that circulate in the animal’s blood. When a mosquito takes a blood meal from that animal, they ingest the microfilariae, which develop to an infective stage inside the mosquito. Once they are ready, the parasites travel to the mosquito’s mouthparts and are transmitted to a victim that the mosquito bites for their next meal.

Heartworm signs in pets

Heartworms can parasitize dogs and cats, but they affect each species differently.

  • Dogs — Since dogs are a natural heartworm hosts, the parasites can thrive inside an infected canine. The heartworm larvae travel to the blood vessels that supply the dog’s lungs and make themselves cozy. Female worms can grow up to 14 inches long and, in severe cases, hundreds of worms can parasitize one dog. Heartworm disease mostly causes heart related problems in dogs, because the parasites’ presence causes inflammation and vessel thickening that make it difficult for the heart to pump effectively.

Most dogs don’t show signs in the early stages, and two years can go by before signs, which include lethargy, lagging behind on walks, increased panting, a soft, persistent cough, decreased appetite, and weight loss, are noticeable. As the heart is more compromised, the dog may develop a swollen belly caused by fluid accumulation in the abdomen. Dogs who have a high worm load can experience a condition called caval syndrome, which occurs when the heartworms block blood flow through the heart. Signs include labored breathing, pale gums, and collapse.

  • Cats — Cats are atypical heartworm hosts, and their immune system reacts strongly to the presence of heartworm larvae. However, the parasites can still cause significant health problems for an infected feline—the larvae reach the cat’s lungs, trigger a severe inflammatory response, and cause heartworm-associated respiratory disease (HARD). Signs include vomiting, difficulty breathing, increased respiration and effort, and in some cases, sudden death. While heartworms don’t typically grow to adulthood in a cat, only one or two mature worms can easily block a cat’s tiny heart.

Heartworm treatment in pets

A golden retriever lies calmly on a table while a veterinarian administers an injection. A woman gently holds the dog, providing comfort. The scene is bright, with both people wearing casual clothing.

No medication is available to safely treat heartworm disease in cats, and treatment involves supportive care to stabilize the cat and address the inflammation caused by the parasites. Treatment in dogs is a lengthy, potentially dangerous process that involves stabilizing the dog and killing the heartworms at every life stage. 

Therefore, year-round prevention is the best way to protect all pets from heartworm disease and its deadly consequences.

Pet owners have numerous options to ensure their pet is protected from heartworms. You can administer oral or spot-on treatments monthly, or our Memorial Villages Animal Hospital team can administer a ProHeart injection that protects your dog all year long. Contact us today to learn about our June ProHeart discount.