Heartworms cause heart, lung, and other organ system damage in dogs and cats, and Scripps Ranch Veterinary Hospital wants to partner with you in preventing pet heartworm disease. Read on for answers to frequently asked questions about canine and feline heartworm disease diagnosis, treatment, and prevention.
Question: What is heartworm disease in pets?
Answer: Heartworms are parasitic, foot-long worms that live in your pet’s bloodstream. When the adult worms, which can number in the hundreds, lodge in your pet’s heart and pulmonary arteries, inflammation and blockage ensue, leading to heart failure. The decreased blood flow and weakened heart cause pale gums, weight loss, and fluid buildup in the abdomen and liver.
Q: Are heartworms in pets contagious?
A: Animals catch heartworm disease when an infected mosquito bites, and transmits larvae to your pet through the skin puncture. Over the next six months, the larvae migrate to your pet’s heart and become adults. The adults produce more larvae, which mosquitoes ingest when they bite and draw a blood meal from your pet. Thus, dogs are not directly contagious to each other, but dogs living in the same area can all become positive, because the mosquitoes in that area are carriers. Wildlife such as wolves, coyotes, and foxes can also become infected with heartworms and serve as infection reservoirs.
Q: Can cats get heartworm disease?
A: While cats are not ideal heartworm hosts, they can become infected and develop life-threatening illness. Cats are less likely than dogs to become infected from a mosquito bite, and they usually harbor low worm numbers. Those few worms, however, produce severe inflammation (i.e., heartworm-associated respiratory disease [HARD]). Heartworm-infected cats may cough and struggle to breathe, or develop weight loss and vomiting, and some cats die suddenly without any warning. No safe heartworm treatment is available for cats.
Q: What are heartworm disease signs in pets?
A: Dogs who have recently been infected, or who harbor only a few worms, may show no signs of a problem at first, but as the worms multiply, they will develop a cough, show decreased exercise tolerance, and lose weight. The worms’ presence ultimately causes heart failure, with abdominal distention from fluid buildup. Some dogs with advanced infestations (i.e., caval syndrome) will suddenly collapse, and will die if the worms are not surgically removed.
Q: How is heartworm disease diagnosed in pets?
A: The team at Scripps Ranch Veterinary Hospital can perform a quick pet-side heartworm test with only a few drops of blood. This antigen test reveals whether adult worms are in your dog’s heart. We can also check for the presence of immature heartworms in the bloodstream with a microfilariae test. If your dog tests heartworm positive, further testing will be required to stage their disease, which may include a complete blood count, blood chemistries, urinalysis, chest X-ray, and ultrasound. Testing is less accurate in cats, and false negatives are common.
Q: How is heartworm disease treated in dogs and cats?
A: Heartworm treatment is a multi-step process that takes several months. We first develop a customized treatment plan for each heartworm-positive dog. Treatment usually starts with prescribing a tetracycline antibiotic to weaken the worms. Next, the dog is given medication to kill the immature worms in the bloodstream, and an anti-inflammatory medication to help moderate the pet’s reaction to the worms. At appropriate times and intervals, injectable medication will be given to kill the adult worms. Exercise restriction, which must be enforced for months, is a crucial treatment component, because exercise causes a dog’s heart to pump more strongly, potentially sending dead worm pieces through the bloodstream, and causing a severe complication called thromboembolism. Kennel or house confinement with short leash walks only is best.
No safe heartworm treatment exists for cats, but medication can be given to control their symptoms and make cats more comfortable.
Q: What is the prognosis for pets with heartworm disease?
A: The prognosis for dogs with stage one or two heartworm disease is good, and with treatment and time, their damaged heart and blood vessels can heal. Dogs with stage three heartworm disease have a guarded prognosis, and a higher risk of treatment complications. Stage four heartworm disease dogs have organ system failure, and often do not survive.
Q: How can I prevent heartworm disease in my pet?
A: The good news is that heartworm disease is entirely preventable in cats and dogs. Several heartworm prevention options are available, including oral or topical monthly preventives, which many pet owners prefer, and which can be combination products that can control fleas and intestinal parasites, in addition to heartworms. If a monthly product does not fit your schedule, injectable canine heartworm prevention that lasts for 6 or 12 months is available. Heartworm prevention also requires environmental management to decrease mosquito habitats by eliminating standing water in your yard, and considering mosquito control and repellents.
Our Scripps Ranch Veterinary Hospital team wants you and your pet to avoid the heartbreak of heartworm disease. Call us, and together we will set up a heartworm testing and prevention plan to avoid the stress and risks of heartworm disease and treatment—for you and your pet.