April is Heartworm Awareness Month
In honor of heartworm awareness month, here are some tidbits you may not know about heartworm disease in cats and dogs.
What is Heartworm Disease and What Causes It?
Heartworm disease is a serious, sometimes fatal disease in pets. It is caused by a parasitic worm called Dirofilaria immitis. The worms are spread through the bite of a mosquito. They are called “heartworms” because the adults live in the heart, lungs, and associated blood vessels of an infected animal (1).
Heartworm in Dogs
When the mosquito bites the dog, the dog becomes a natural host for the heartworms. The heartworms then live inside the dog, grow into adults, mate and produce offspring(2). In a newly infected dog, it can take about 6 to 7 months for the larvae to mature into adult heartworms. If left untreated in a dog, a heartworm’s lifespan is 5 to 7 years (1).
Heartworm in Cats
Heartworm disease in cats is very different from heartworm disease in dogs. The cat is an atypical host for heartworms, which means most worms in cats do not survive to the adult stage. Because of this, heartworm disease often goes undiagnosed in cats. It is important to understand that even immature worms cause real damage in the form of a condition known as heartworm associated respiratory disease (HARD) (2).
What are the Signs and Symptoms of Heartworm Disease?
In the early stages of the disease, many dogs show few symptoms or no symptoms at all, especially of the number of worms they have is low. If the worm count is higher- general loss of body condition, a persistent cough, and tiredness after mild activity can serve as symptoms. In moderate to high levels of heartworm disease in dogs, heart and lung changes are usually seen on chest x-rays(1).
For cats, signs of heartworm disease can be very subtle or very dramatic. Subtle symptoms may include coughing, asthma-like attacks, periodic vomiting, lack of appetite, or weight loss. Occasionally an affected cat may have dramatic symptoms such as difficulty walking, experience fainting or seizures(2).
How Do You Know if Your Pet has Heartworms?
If you have not already done so, test your pet for heartworm ASAP! Heartworm disease is a serious, progressive disease. The earlier it is detected, the better the chance of recovery for your pet. The best and easiest way to check if your pet is infected is by having your vet take a small blood sample. This works by detecting the presence of heartworm proteins in the blood. Keep in mind annual testing is necessary to ensure that the prevention program is working(1).
Heartworm infection in cats is harder to detect than in dogs, because cats are much less likely than dogs to have adult heartworms. The preferred method for screening cats includes the use of both an antigen and an antibody test(2).
Prevention is the Best Treatment!
If your pet is healthy, taking preventative measures is your next step. Most preventative products are FDA-approved to prevent heartworms in dogs. All of them will require a veterinarian’s prescription. Most products are given monthly, either as a topical liquid applied on the skin or as an oral tablet(1).
If your pet is tested positive, your first step is to restrict your pets exercise. Your dog’s normal physical activities must be restricted as soon as the diagnosis is confirmed, because physical exertion increases the rate at which the heartworms cause damage in the heart and lungs(2).
Once your veterinarian has determined your dog is stable and ready for heartworm treatment, he or she will recommend a treatment protocol involving several steps. The American Heartworm Society has guidelines for developing this plan of attack, the treatment regimen for heartworm can be both expensive and complex (2).
Approximately 6 months after treatment is completed, your veterinarian will perform a heartworm test to confirm that all heartworms have been eliminated. To avoid the possibility of your dog contracting heartworm disease again, you will want to administer heartworm prevention year-round for the rest of your pet’s life(2).