As a pet owner, you have probably heard of heartworms, but do you truly know what they are? Are your dogs and cats protected from them? The unfortunate truth is that many aren't, and the lack of protection means more than 1 million dogs around the world have fallen victim to heartworm disease. Of course, there is no better time than now to educate yourself! April is National Heartworm Awareness Month. Read up on this misunderstood disease to learn how to protect your pets.
What Are Heartworms?
A heartworm is a small parasite that infects animals via mosquito bites. An immature worm known as a microfilaria enters the bloodstream while the mosquito eats. About two months later, the worms reach the heart and begin to grow. After about six months, the worms are mature. Over time, the inflammation caused by heartworms damages the heart, lungs, and arteries. Heartworms are most common in dogs, but they can live in cats and ferrets as well. However, cats are not a typical host, and most worms don't survive to adulthood, making the problem particularly hard to diagnose in felines.
How Can I Prevent My Pet From Getting Heartworms?
Control your environment first. Eliminate places on your property that could act as a mosquito breeding ground, such as old pools, uncovered rain barrels, and puddles caused by leaky garden hoses. Set mosquito traps as well, and avoid allowing your dog to play in the yard at dawn and dusk, which is when mosquitoes are most active.
Preventative medication is important as well. Even though mosquitoes aren't typically active in cold weather, veterinarians recommend administering heartworm medication all year for the best results. Sticking to the dosing schedule is essential for keeping heartworms at bay. Use FDA-approved mosquito repellents around your home, and if you expect to have your pets outdoors during prime feeding times, wipe them down with a product such as Vetri-Repel Pet Wipes.
Which Pets Should Be Tested for Heartworms?
Even if you follow your veterinarian's heartworm prevention regimen exactly, you must have your dog tested at least once per year. If you have a puppy younger than 7 months old, test him before beginning preventative medication. Since heartworms can take months to be detected, puppies also need tested six months after beginning medication. If your dog is at least 7 years old and has never been on preventative medication, he needs a test. Finally, if your dog misses a preventative treatment, test him. Because heartworms are harder to detect in cats, the veterinarian must use an antibody test and an antigen together to detect exposure. Sometimes, an ultrasound or x-ray is required. Have your cat tested before starting heartworm prevention medication and again according to the veterinarian's instructions.
What Are the Symptoms of Heartworms?
Heartworms are separated into four classes of infection, and symptoms increase in severity as the class does. Class ones typically don't exhibit symptoms, although your dog may have a mild cough. In stage two, your dog may get winded after exercise and develop a more persistent cough. By stage three, you may hear abnormal sounds in your dog's lungs, notice a weak pulse, see a decreased appetite and weight loss, or notice a swollen belly. Class four heartworms are known as caval syndrome. This life-threatening class presents itself with coffee-colored urine, labored breathing, and pale gums.
Most cats do not exhibit symptoms at all. If your cat does show symptoms, they may present as asthma attacks, excess coughing, and vomiting. He might also lose his appetite and begin to lose weight. Some heartworm-positive cats have seizures, faint, or have trouble walking.
How Do Veterinarians Diagnose Heartworms?
A veterinarian can often tell if your pet has heartworms with a simple blood test. The test checks for traces of the antigens produced by microfilariae. If the test detects heartworms, further tests are required to determine whether treatment is safe. A combination of echocardiograms, radiographs, and ultrasounds tell the veterinarian whether there are worms in the heart chamber, whether there are abnormalities in the pulmonary arteries, and whether the heart is abnormally shaped or has active worms, respectively.
Blood tests aren't as accurate for cats, as fewer than 20% of them show microfilariae in the blood. If your veterinarian suspects your cat has heartworms, he or she may do an eosinophil count to determine if the white blood cells are elevated. Other diagnostic options include ultrasounds, x-rays, or antibody and antigen tests. Unfortunately, early detection of heartworm disease in cats is quite difficult.
What Are the Treatment Options for Heartworms?
Immediately after an official diagnosis, your veterinarian will tell you to restrict your dog's activities. Too much physical activity puts strain on the heart and lungs. If your dog won't rest on his own, crate confinement will be essential. Dogs with advanced heartworms or other medical conditions may need to undergo other treatments first to ensure stability. Once stable, your veterinarian will use an intramuscular injection of melarsomine dihydrochloride, an FDA-approved treatment, to kill the heartworms. He or she will also prescribe imidacloprid and moxidectin to remove microfilariae from the bloodstream. If the heartworms are extreme, the veterinarian may perform surgery to pull the worms out one by one. Follow-up testing will be necessary to ensure the treatment worked.
Unfortunately, there is no treatment to get rid of heartworms in cats. The medication used on dogs is not safe for them and no other drugs are available at this time. However, with ongoing veterinary care and a long-term care plan, your cat may have the chance to stabilize and continue to live a happy life.
Now that you know the dangers of heartworms and how to prevent or treat them, it's time to protect your pets. Contact your veterinarian to schedule a heartworm test for your dog or cat today.