Heartworm disease often goes undiagnosed in cats, but that doesn’t mean the worms aren’t present
By Kim Campbell Thornton
Andrews McMeel Syndication
You probably think of heartworm disease as a problem in dogs, but that’s a misconception -- one that can be deadly for cats.
Cats are not typical hosts for heartworms (known scientifically as Dirofilaria immitis), but they can acquire the spaghettilike freeloaders through the bite of a mosquito that has fed from an infected dog, fox or coyote. That bite injects infective larvae known as microfilaria into the body, where they enter the bloodstream and begin their life cycle, setting up housekeeping in the heart, lungs and associated blood vessels.
Don’t assume your cat is safe if she doesn’t go outdoors. Approximately one-third of infected cats acquired the disease even though they lived indoors.
Although they may have as few as one to three adult heartworms, because cats are so small relative to dogs, that small number is still considered to be a heavy infection. Even if they have no adult heartworms at all, immature ones can still damage a cat’s heart, causing respiratory signs such as coughing, gagging, difficulty breathing or asthmalike attacks. The lungs can develop blood clots or become inflamed. These signs are known as heartworm-associated respiratory disease, or HARD. Cats with heartworms typically have clinical signs that are more severe than those in dogs.
Heartworms don’t limit themselves to the heart and lungs. They can migrate to the brain, eyes and spinal cord. If they mature, heartworms can live two to three years in a cat’s body.
One reason heartworms go unnoticed is that they are difficult to detect in cats. Physical signs usually don’t occur until infection is well established.
Clinical signs can appear suddenly and include salivation, trouble breathing, vomiting and diarrhea, collapse, and neurologic signs such as altered mentation, blindness and seizures. More often, cats have vague chronic signs: poor appetite, vomiting that’s not associated with eating, lethargy, weight loss, exercise intolerance, cough, wheezing, or increased respiratory rate and effort.
Sometimes the only sign is sudden and shocking: death.
A blood test is necessary to check a cat’s heartworm status. For the most accurate results, your veterinarian may recommend using an antigen test to detect adult worms and an antibody test to detect larvae. Heartworms can also be discovered through X-rays or a heart ultrasound.
Prevention is the best medicine when it comes to feline heartworm disease because no treatment is available for them. Dogs can undergo a series of painful intramuscular injections of a drug to kill the worms, but that medication is toxic to cats.
In some cases, feline heartworm infections disappear on their own because cats are not appropriate hosts, or because the cat’s body develops an immune response that kills the worms. It’s not something you can rely on, however, and cats can still develop HARD before the worms die off.
While heartworm disease in cats can’t be cured, the signs can be managed. Supportive treatment such as intravenous fluids and oxygen therapy, as well as certain cardiovascular drugs and antibiotics and medication to control vomiting can help infected cats. Steroids can help to manage respiratory signs. In a best-case scenario, your cat’s condition will stabilize and be manageable over the long term.
Your veterinarian can prescribe monthly topical or oral preventive medication for your cat and advise you on the recommended treatment for your area. Some heartworm preventives are also effective against other intestinal and external parasites, including roundworms, fleas and ear mites, so they provide a double whammy when it comes to protection. Your cat will need to be tested free of heartworms before you start giving any preventive.
all June long
-- Get ready to celebrate your pets in June. It’s Adopt-a-Cat Month, National Foster a Pet Month, National Microchipping Month and National Pet Preparedness Month. Also coming up is Pet Appreciation Week (June 6-12). Special pet days in June are Best Friends Day and World Pet Memorial Day (both on June 8), National Dog Party Day (June 21), Take Your Cat to Work Day (June 21), followed, naturally, by Cat World Domination Day (June 24) and Take Your Dog to Work Day (June 25).
-- You’ve probably seen a sundog, a circular bright spot on one or both sides of the sun, usually when the sun is near the horizon. Astronomers call this phenomenon a parhelion, or parhelia when there are two of them. But why is it nicknamed “sundog”? The word was first recorded between 1625 and 1635, but lexicographers are unsure of its origin. One theory is that it comes from Norse mythology and refers to constellations of two wolves hunting the sun and moon. In English, the word dog can be a verb meaning “hunt, track or follow” -- the way our dogs dog our footsteps, for instance -- so it may be a reference to the way the parhelion seems to follow the sun.
-- Considering a new pet? Bunny lovers say rabbits combine the best features of both dogs and cats. Like dogs, they are social and affectionate. Rabbits are highly trainable, including learning to use a litter box like a cat. They don’t need to be walked and are content to live as quiet indoor companions -- provided they have enough room to exercise and fun toys to challenge their brains. Bonus: Bunnies are herbivores, so their poop doesn’t stink. Tip: Rabbits chew and dig and they have special dietary needs, so it’s important to educate yourself. (Try reading one of our previous columns for more information: bit.ly/3uYn0CN.) -- Dr. Marty Becker, Kim Campbell Thornton and Mikkel Becker
ABOUT PET CONNECTION
Pet Connection is produced by a team of pet care experts headed by “The Dr. Oz Show” veterinarian Dr. Marty Becker, founder of the Fear Free organization and author of many best-selling pet care books, and award-winning journalist Kim Campbell Thornton. Joining them is behavior consultant and lead animal trainer for Fear Free Pets Mikkel Becker. Dr. Becker can be found at Facebook.com/DrMartyBecker or on Twitter at DrMartyBecker. Kim Campbell Thornton is at Facebook.com/KimCampbellThornton and on Twitter at kkcthornton. Mikkel Becker is at Facebook.com/MikkelBecker and on Twitter at MikkelBecker.
Q: Our dog is obsessed with chasing squirrels! Is there any way to get him to leave them alone?
A: Dogs are indeed passionate about protecting their yards from the furry tree climbers.
Some are determined to find and eliminate squirrels, sniffing their trails hours after squirrels have returned to their nut stash. That can become hazardous if dogs escape the yard in pursuit of their prey. Dogs who can’t resist the urge to stalk squirrels need other ways to channel their predatory and chase behaviors.
There are a few ways to redirect your dog’s attention away from squirrels, and your success may depend on whether your dog is intrigued by the scent or the presence or motion of squirrels. Try the following methods to see what works best. And consider keeping your dog close to you on leash in the beginning to help him stay focused and not be tempted by the squirrels.
Scent games are one way to redirect your dog’s desire to pursue interesting smells. A simple version of “find it” is to scatter kibble in the grass and let your dog search for it. Doing this once or twice a day can help channel your dog’s focus away from squirrels, and give him something else to do when he's in your yard.
If your dog’s favorite part of squirrel hunting is the chase, turn the sight of a squirrel into an opportunity to engage with you by immediately bringing out a toy such as a flirt pole. You can also use "come when called" to turn a squirrel sighting into a fun game of canine tag, followed by treats to reinforce the behavior.
If your dog’s chase behavior is becoming a concern, contact your veterinarian for guidance and potential partnership with a reward-based trainer or referral to a veterinary behaviorist. -- Mikkel Becker
Do you have a pet question? Send it to firstname.lastname@example.org or visit Facebook.com/DrMartyBecker.