Heartworm Disease on the Rise

by Steve Dale

Experts stop short of calling it an epidemic, but the newly-released results of a nationwide survey indicate that the number of heartworm cases is rising. As a result, it's also likely that more pets are dying of the disease.

The tragedy is, heartworm disease in dogs, cats and ferrets is totally preventable.

To enhance awareness, the American Heartworm Society and Merial (manufacturer of a heartworm preventative) have kicked off a campaign called "April as Heartworm Awareness Month." The goal is to help veterinary professionals educate the public about the potentially deadly disease.

The explanations for the hike in heartworm are varied, but it seems that compliance -- actually administering the preventative medication -- is the biggest problem, according to Dr. Sheldon Rubin, president of the American Heartworm Society.

According to a second survey, released in March, of approximately 1,000 dog owners, 35 percent who took their dogs to a veterinarian annually failed to give the pets a preventative.

Many people mean well, says Rubin, but forget to give the medication. "I can't tell you how often I prescribe the monthly preventative, then a year later the client says, 'I can put off buying more because I have three or four doses left.' Well, how can that be if they're using it each month?" he commented.

Another explanation for the erratic use of heartworm preventative may be the economy.

"Using a monthly product every other month isn't really saving money; instead, it's taking a chance with your pet's life," says Rubin, of Chicago. "A couple of Starbucks a month is probably less than the cost of protecting your best friend by using the monthly products as directed." Rubin calls another problem the "It won't happen to me syndrome."

"People somehow just believe it can't happen to them - that their pet just won't meet that infected mosquito (infected mosquitoes carry heartworm)," he notes.

Most heartworm preventatives are chewables, or topicals applied between a pet's shoulder blades each month. There's another option that works for six months at a time: ProHeart 6. A veterinary visit is required to use ProHeart 6 since it's injected, like a vaccine.

"Obviously, one benefit (of ProHeart 6) is that compliance isn't an issue; you know your pet is protected for six consecutive months," says Rubin. "But then there are restrictions concerning the usage of ProHeart 6" (an FDA-mandated RiskMAP, which includes special veterinary training to use the drug, as well as mandating client signatures before the product is used).

ProHeart 6 does not protect against intestinal parasites, such as hookworm, roundworm, whipworm and/or tapeworm, Rubin notes. However, the monthly heartworm medications provide protection against some or all of those nasty buggers.

"Not only don't you want your dog to come down with worms; these same worms can potentially be transmitted to people, most often children," says Dr. Lynn Buzhardt, a Zarchary, LA-based board member of the American Heartworm Society.

Results from the heartworm survey were distributed to more than 40,000 veterinarians last fall.

Veterinary practices from some 2,200 counties were represented. The survey confirmed that heartworm disease now occurs in all 50 states, and that in many parts of the country it's being reported more often than ever before. One estimate is that 40 percent of dogs aren't protected against heartworm, and it's clear most cats (well over half) are not protected.

Another explanation for the increase in heartworm is offered by Dr. Jorge Guerrero, Pennington, NJ-based board member of the American Heartworm Society.

"Maybe people are unaware of heartworm all together, or don't believe how serious this disease can be," he notes.

It turns out the survey confirms Guerrero's assertions: Most people surveyed seemed to believe the disease was easily treated.

Rubin explains that when some mosquitoes bite dogs, they transmit a "baby heartworm," called a microfilaria. These microscopic parasites ultimately transform into 6- to 12-inch spaghetti-sized heartworms. Infected dogs may have dozens of heartworms clogging their hearts and lungs. No wonder they often have shortness of breath and are reluctant to exercise. Without treatment, they can die. Treatment success isn't guaranteed, and it's not cheap.

"If there's heartworm in dogs where you live, it's a good bet the disease is occurring - sometimes undetected - in cats, as well," Rubin notes. Symptoms of feline heartworm association respiratory disease include shortness of breath and coughing. Sometimes these symptoms may be mistakenly diagnosed as feline asthma. Another symptom of heartworm disease in cats is sudden death. In any case, there's no treatment for heartworm in cats. That's why prevention is so vital.

"The bottom line is that veterinarians have an arsenal of safe options at their disposal to fight off heartworm," says Rubin. "Heartworm is serious; it does kill. Talk to your veterinarian about which product is best for your circumstances."

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