Heartworm Be Gone!
How to keep these pests from hurting your pet.
By: Elaine Waldorf Gewirtz

What is Heartworm Disease?
Heartworm disease is a serious problem caused by Dirofilaria immitis, a parasite that thrives mostly in warm, humid climates and is transmitted to cats and dogs via mosquitoes. However, "Heatrworm is present in just about ever are of the United States," says Dr. Donald W. Doiron, president of the American Heartworm Society, which estimates that 27 million dogs are not protected against this deadly infection.
A small female mosquito spreads the disease when it bites an infected animal and ingests very tiny larvae that live in the blood. Eight days to a month later, when the pest bites a healthy pet, it deposits the larvae, which mature and travel throughout the pet's body.
"Adult Dirofilaria can grow up to 11 inches, and they live inside the chambers on the right side of the heart and in the pulmonary arteries and cause damage," says Dr. Allan J. Paul, professor of parasitology at the University of Illinois College of Veterinary Medicine in Urbana, Illinois. A dog could be infested with a heavy load of worms, which can interfere with and damage the heart and other vital organs by blocking the flow of blood and making the heart strain to pump it through the vessels.

If an infected mosquito bites your dog, you may not notice any change in his health right away. It can take several months to a year for the first signs of disease, which include persistent coughing or fatigue, to show up. Your veterinarian can determine if your pet has heartworm through a simple blood test.
Heartworm is totally different disease in cats than in dogs, however. Cats may only have one to two worms, which live in the lungs instead of the chambers of the heart. "The cat may have bronchitis or asthma from an inflammatory reaction in the lungs," says Dr. Charles t. Nelson of the Animal Medical Center in Anniston, Alabama. "The usual signs of heartworm may not show up until quite a bit of irreversible tissue damage has occurred."

Remember, it only takes one mosquito to infect your pet. Both indoor-only cats and dogs that make quick trips to the backyard are just as likely to get heartworm. Mosquitoes always manage to squeeze themselves through small openings in screens, doors, and windows and can easily pick up heartworm from stray dogs and cats in the neighborhood that aren't taking preventive medication. "That's why trying to limit the environment alone by keeping your pet indoors isn't going keep your dog or cat from getting heartworm," says Dr. Paul

The Power of Prevention
Although heartworm is very dangerous and can be fatal, there is hope for your furry friends. Several preventive medications that are 100% safe and effective are available from your veterinarian. They even come in flavored tablet and chewable forms to make them easy to give your pet so it seems more like a treat than medication. Some oral preventives are administered daily, others once per month. There is also an injection that your veterinarian can give your pet once every 6 months.

Which one should you give your pet? All are effective, but you should talk to your veterinarian about the options available before making a decision. "The biggest problem is that owners forget about the medication which leaves their pets unprotected," says Dr. Doiron. "With all of these medications so easily available, there is no reason why any dog should get heartworm."

While they kill the larvae before they can mature and clog the blood some medications can also control other parasites such as hookworms, roundworms, and whipworms, (see Protect Your Pet! to learn more about these parasites). A blood test given by your veterinarian once a year is recommended by the American Heartworm Society to test for heartworm.

Treating Heartworm
If your dog does become infected with heartworm, rest assured that treatment is available. "In most cases, the dog can make a full recovery, depending upon how far the disease has progressed," claims Dr. John W. Mccall, a parasite specialist at the University of Georgia College of Veterinary Medicine. Unfortunately such options don't exist for treating heartworm is cats, making prevention for our feline friends even more necessary to keep them healthy.

The best thing you can do to help your pets stay healthy indoors as well as out is to get them tested, be vigilant about giving them heartworm prevention medication regularly, and visit your veterinarian for regular checkups. Don't give parasites a chance to set up permanent residence inside your pet. The buzz is that you're the one in charge, not the mosquitoes.

Elaine Waldorf Gewirtz is the author of six pet books. Including Pugs for Dummies (Wiley). She frequently writes on animal health care issues.

The Low Down on Heartworm

Heartworm has been reported in all 50 states of the U.S., with higher incidence in Texas, Florida, Louisiana, North Carolina, Georgia, Mississippi, Tennessee, South Carolina, Alabama, and Indiana.
Preventive medication is available for puppies as young as 8 weeks of age.
Cats can get heartworm and should receive preventive medication.
Mosquitoes infected with heartworm can transfer it to both indoor and outdoor pets. Secure any openings in screens and doors as tightly as possible.
Pets should be kept indoors in the late afternoon and evenings when mosquitoes are most active.
Standing pools of water around your property, where mosquitoes often breed, should be removed.
Be sure to discuss a method of heatworm prevention with your veterinarian and choose one that can be given to your pet on a regular basis year-round.
Make sure your veterinarian tests your pet once a year for the presence of heartworm.