Unprotected pets at risk for heartworm disease

By Dr. Marty Becker

Knight Ridder Newspapers

This time of year is fun for all family members, pets included, but it brings us into the crosshairs of the dreaded mosquito. While mosquitoes are mostly a nuisance, bringing itching and scratching to humans (although West Nile Virus is now a concern in some parts of the country), they pose a serious health threat to dogs and cats.

All pets are at risk from heartworm -- a silent killer that is spread through mosquito bites. Heartworm is a potentially life-threatening disease that infects a dog's and cat's heart and lungs. More alarming is the fact that heartworm disease has been found in all 50 states. It takes only one mosquito bite from an infected mosquito to infect a dog and cat with heartworm disease.

Unfortunately, although heartworm is a serious condition, many pet owners don't take seriously. In fact, a 2001 Gallup survey found that only 55 percent of dog-owning households were on some form of heartworm preventive, down from a high of 66 percent in 1998.


Pet parents have much to be worried about. According to a recent survey by the American Heartworm Society, at least 250,000 dogs and cats tested positive for heartworm infection nationwide. This survey, the first of its kind since the 1950s, indicates that at least one in 250 dogs may be at risk for heartworm infection. This may not seem high at first blink, unless the infected pet is your dog or cat.

"The importance of this survey should not be overlooked," said Dr. Doug Carithers, senior director, Veterinarian Professional Services, which was the sponsor of the survey. "This survey demonstrates that heartworm disease continues to be a problem that pet owners need to seriously consider. Once their dog or cat has been infected with heartworms, the only option available to pet owners is medical or surgical treatment."

Many pet owners fail to realize that heartworm disease is easier and significantly cheaper to prevent than treat. Dogs and cats may not show signs of illness until the disease has already ravaged their heart and lungs, leaving pet owners with few options. Symptoms, which include fatigue, weight loss and a chronic cough, often don't appear until the parasitic heartworms, have colonized the heart and lungs, causing damage to these organs and, ultimately, leading to death.

While it can take 15 to 19 heartworms before dogs show any sign of illness, as little as one heartworm can be fatal to cats. The safer option for pet owners is prevention.

It is important to know that before starting a preventive program, dogs and cats should first be tested for pre-existing heartworm infection, otherwise the preventative medicine could harm them. There are a number of effective heartworm preventives that pet owners can obtain from their veterinarians.

For example, the product I use on my own pets, Heartgard Plus, not only protects against heartworms, it also controls intestinal parasites, like roundworms and hookworms. While some preventives may be cumbersome to administer and painful, Heartgard Plus comes in a real beef-chewable that dogs wolf down and woof with delight.

Although heartworm disease can be found in every state, the Southeast is experiencing the highest number of cases. In 2001, the top 10 states reporting the highest number of heartworm incidence were Texas, Florida, Louisiana, North Carolina, Georgia, Mississippi, Tennessee, South Carolina, Alabama and Indiana.

Pet owners wishing to learn more about preventing heartworm, protecting pets from other summertime threats, such as fleas and ticks, and the importance of scheduling regular visits with the veterinarian can visit or call 1-866-ASK-VETS.

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