Don’t Forget Your Pet’s Heartworm Preventive!

O

ver a million pets in the United States are diagnosed yearly with heartworm disease. Of all states, dogs in Mississippi have the highest annual incidence. Almost 10% of Mississippi dogs will test positive for heartworms. Our neighbor Louisiana runs a close second.

Heartworm infection is a serious, potentially deadly condition caused by a parasitic worm transmitted through mosquito bites. Although heartworms are known to cause disease primarily in dogs, cats, and ferrets, they also infect wild animals.

Adult heartworms living in a pet's heart and lungs mate and produce offspring called microfilariae. These microfilariae circulate in a pet's bloodstream. When a mosquito bites your animal, the mosquito can pick up the microfilariae and eventually transfer them to another unsuspecting animal it bites. Once these baby heartworms enter an animal's body, they continue to grow up to a foot long within a few months. These worms eventually end up in the heart, lungs, and surrounding blood vessels.

Dogs are natural hosts for heartworms and serve as the primary reservoir of infection. Although the average number is usually far less, dogs can have several hundred adult worms.

Cats are atypical hosts, and when infected, they usually have only one or two heartworms. In an otherwise healthy cat, most immature heartworms get destroyed by the pet's immune system and don't develop into adults.

How will your pet act if it has heartworm disease? It depends upon your pet's age, overall health, and the number of worms present. Some animals don't act sick. But, as time passes, the number of heartworms increases and causes more damage to your pet's heart and lungs. Your four-footed friend may cough, tire easily, have a diminished appetite and lose weight. In severe cases, a dog's heart may fail and cause the belly to fill with fluid and look distended.

Cats with heartworms may cough or wheeze. They may become picky eaters, throw up, and even lose weight. In some cases, a cat may appear to faint, have a seizure, or have difficulty walking. A cat with heartworm disease can even collapse or die without showing any previous signs of illness.

How will you know whether your pet has heartworms? Your dog can usually be diagnosed with a quick blood test in your veterinarian's office. Since cats typically have fewer heartworms than dogs, determining if your cat is infected can be more challenging and often requires additional blood tests, xrays, and ultrasounds.

Treatment of heartworms involves several months of staged medications and exercise restriction. Heartworm infection in an otherwise healthy dog is often successfully treated. Generally, the earlier the disease is diagnosed and treated, the better the prognosis. However, the damage heartworms leave behind may be permanent.

Unfortunately, the medication that effectively clears adult heartworms in dogs cannot be used in cats. Instead, treatment in cats is focused on helping prevent additional heartworm infections and providing supportive care.

The good news is that you can effectively prevent your dog, cat, or ferret from developing heartworm disease through regular, yearround administration of an Fda-approved heartworm preventive. Options include chewable tablets, topical “spot-on” solutions, or an annual injection. Some heartworm preventives products also contain flea, tick, and intestinal parasite preventives.

Heartworm prevention is available by prescription from your veterinarian. We recommend you start giving the preventive at your puppy or kitten's first visit. Dogs older than six or seven months need a heartworm test before their first dose of prevention. Giving heartworm preventive to a dog with heartworms can be dangerous, so please don't skip that heartworm test. Your dog will also need to get tested for heartworms annually, even if you don't miss a preventive dose.

Heartworm preventive works very well to prevent heartworm infection so long as your pet receives it regularly. It won't work well if you are late or skip even a single dose. However, not all heartworm preventive is one-hundred percent effective.

It is not uncommon for even the best-intentioned pet owners to forget to give heartworm preventive. Tablets or topical solutions need to be given year-round on the same date each month. One new topical product for cats (Bravecto Plus) only needs to be applied every two months.

Give your pet its heartworm preventive on the day of the month that's easy for you to remember. Our four dogs receive their medication on the first day of every month. If you find it challenging to remember to give your dog monthly preventive, maybe you should consider using a heartworm prophylactic injection that only needs to be repeated once every 12 months.

Do you think your pet doesn't need heartworm preventive because it spends all day sleeping in the house? You're not off the hook. Mosquitoes come indoors, so all dogs, cats, and ferrets need to receive year-round heartworm preventive.

How else can you protect your pets from getting heartworms? Reduce their contact with mosquitos. You can start by removing sources of stagnant water around your property. Try to keep your pet indoors during the times of day when mosquitoes are most actively feeding. You can also discourage mosquitos from biting your dog by using an Epa-registered topical mosquito product labeled to repel and kill mosquitos in dogs. We are not aware of any available Epa-registered similar products approved for use in cats.

We would love to see fewer animals get heartworms. The key is prevention. Your veterinarian can test your pet for heartworms and discuss which preventive or treatment options may be best suited.

Are you thinking of getting a dog or cat? Our local animal shelter is filled with animals that long for a loving home. If a dog in the shelter is “heartworm positive,” there is no reason to pass it up. The shelter may offer to treat the heartworms at no additional cost. We adopted our Labrador retriever James, a “heartworm positive” dog, from the Oktibbeha County Humane Society last year and are so happy that we made him a part of our family. We urge you to do the same.

Those of you interested in learning more about heartworms can also visit the American Heartworm Society website at www. heartwormsociety.org

We invite you to email us questions about animal care that you would like us to address in our monthly “Ask the Vets” column. This publication is designed to provide general information regarding the subject matter covered. We encourage you to contact your regular veterinarian should you have specific questions about your pet's medical care.