PART TWO ABOUT HEARTWORM DISEASE DOGS, CATS, AND FERRETSWHY WORRY ABOUT HEARTWORM DISEASE
The first article can be read on our Face Book page, or you can obtain a copy at The Wagging Tail. For dogs it is a very serious concern and here in New Jersey and along the Atlantic coast it is highly prevalent. Heartworms are carried by a mosquito that had bitten a dog already infected with heartworms which are then transmitted to the mosquito who then passes the microfilariae into the bite site of another dog. Giving your pet heartworm preventative, either by injection or chewable tablet, can save your dog’s life, and you a great deal of costly treatment in order to eradicate heartworms in your pet’s heart, lungs, and attached blood vessels, which in a full blown “worm burden” can look like a bowl of spaghetti. Melarsomine dihydrochloride is an arsenic-containing FDA approved drug used to kill heartworms in dogs. It is injected deep into the back muscles for dogs with “stabilized class 1, 2, and 3 heartworm disease. Treatment can be potentially toxic to the dog’s body and can cause serious complications, such as life-threatening blood clots to the dog’s lungs.” It is imperative to get a blood test at your vet’s if you have not been consistently giving the preventative, have changed the type of preventative, or have not begun a program.
Cats, both indoor and outdoor, can also get heartworms after being bitten by an infected mosquito, but they are not considered a natural host like a dog is and they are not prone to the same extent of infection. The worms do not thrive well in a cat’s body. While heartworms can live in an untreated dog for five to seven years, in a cat it is usually three to four years. And the number of worms in a cat, called the worm burden, is relatively low-one or two-while in a dog the burden could get as high as 250. Even so, because of a cat’s small size one or two worms is considered a lot. It takes about a month longer for heartworms in a cat to mature than it does in dogs. “Only 20 percent of cats with heartworm disease have microfilariae in the bloodstream, compared to 80 to 90 percent of dogs with heartworm disease.” And in cats the presence is short-lived. Blood-testing a cat for heartworms is not reliable. Vets must rely on x-rays and an ultrasound of the heart, as well as visible symptoms. Some cats will not show any symptoms and just suddenly die. And any symptoms, like “vomiting, decreased activity and appetite and weight loss” may be misconstrued for other ailments. Also, infected cats may suffer from an intense respiratory dysfunction as immature heartworms die releasing toxins into the bloodstream. This is called (HARD) or heartworm associated respiratory disease, indicated by “trouble breathing, increased respiratory rate, and cough.” It can easily be confused with bronchitis or asthma. Just one dead heartworm can kill a cat. The FDA has not approved any drug to treat heartworms in cats and an ultrasound may leave risky surgery as the only possibility. I never even considered heartworm a threat to my cats and was never advised to put them on any preventative treatment. The conundrum now is the reliability of testing before starting a treatment. At this point in their older lives, I may just have to cross my fingers.
Ferrets are more susceptible to heartworms as dogs are, but their symptoms mimic more a cat’s. Again, blood testing is unreliable so an x-ray of the lungs and an ultrasound of the heart would need to confirm an infection. Ferrets can benefit from using Advantage Multi for Cats (imidacloprid and moxidectin) as a preventative measure.
It is very rare, but humans can also get Heartworm Disease by being bitten by an infected mosquito, but we are not a natural host, so the larvae die before becoming adult worms. Yuck!
Visit the American Heartworm Society’s website at www.heartwormsociety.org for more information
