Pethealth Inc.

Pethealth Inc.

March 25, 2010 09:01 ET

Tiny Parasites Can Fell Even the Biggest Dog

As mosquito season approaches, protect your pets against heartworm

KANSAS CITY, MISSOURI--(Marketwire - March 25, 2010) - Pethealth Inc. (TSX:PTZ) -

Woolly is one lucky mammoth. The massive all-white Pyrenees had been a stray, roaming the woods near a mosquito-infested lake, his only food the scraps provided by sympathetic campers, when he was found and taken to a city shelter.

There, he met Tom Lancaster, an animal lover who was willing to take on the friendly dog – and his health problems.

"He was underweight when we got him from the shelter and we knew they hadn't been testing for heartworms. We pretty much assumed it would be an issue," says the 40-year-old Lancaster.

Sure enough, Woolly turned out to have an advanced case of the potentially fatal heartworm disease, which is carried by mosquitoes. A single bite from an infected insect is enough to pass on the parasites. He also had ehrlichiosis, a disease carried by ticks.

Three months of treatments followed, at a cost of more than $700. Woolly had to be kept still for six weeks following each of two injections with an arsenic-based drug that kills adult heartworms. No walks. He wasn't even allowed to climb stairs.

"We had to confine him to the first floor of the house," says Lancaster, who works as a consultant to non-profits. "It was really difficult. When the other two dogs would go out on walks…well, there's no explaining to one why he can't go."

Woolly had to stay at the vet's for 24 to 48 hours after each injection of Immiticide. Dogs must be kept restrained after treatment because, as the worms die, they break into pieces that can cause fatal blood clots and the effect is more lethal if the dog is exercising.

Heartworm larvae transmitted by mosquitoes grow inside their host to an adult size of as long to 12 inches, and make their way through the bloodstream into an animal's heart and lungs. A dog can have has many as 250 heartworms in its body. Occasionally, heartworms in a severely infected dog will migrate into the large vein between the liver and the heart, where they can cause sudden collapse and death within two to three days, according to the American Heartworm Society.

Dogs that have heartworms usually show no symptoms in the early stages, later progressing to a mild to severe cough, wheezing and difficulty breathing, loss of appetite and weight loss.

Although treatment is expensive, costing as much as $1,000 or more and often requiring hospitalization, heartworm disease can usually be successfully treated.

Today, Woolly – who now tips the scales at 120 pounds – is completely recovered. "He's great," says Lancaster. "He's such a loving dog. I had my mother up here for a visit recently and he just lay at her feet for the entire time."

Woolly was also lucky that his new owner had been given a ShelterCare insurance gift policy at the shelter, which covered the cost of his treatment. "The insurance was wonderful," says Lancaster. "It was my first time having pet insurance, but the shelter heartily endorsed it." When his pet insurance gift policy ran out, Lancaster purchased additional coverage.

All three of his dogs are now on heartworm preventive, says Lancaster. "It's an expense, but it's nothing compared to the expense and trouble and difficulty – and discomfort – of going through heartworm treatment," he says. "Having lived through the experience, I know."

Although heartworm disease is found in all 50 states, it's most prevalent within 150 miles of the Atlantic and Gulf coasts, from the Gulf of Mexico to New Jersey, and along the Mississippi River and its major tributaries, says the Heartworm Society. Among dogs that have not been given heartworm preventive, infection rates of up to 45 percent have been reported in these areas.

You can protect your pets by keeping them away from places that harbor mosquitoes, such as ponds or standing water, and using monthly preventive medication.

Pet owners can find more information on heartworm and how to prevent it by visiting For heartworm medications, pet owners can also visit

Launched in May, 2009, is one of the leading pet adoption and pet authority websites in North America. allows visitors to perform real-time searches for pets available for adoption from more than 1300 North American shelters, browse authoritative pet related articles, have questions answered by pet experts and participate in an active pet community. To experience all this and more, visit

About The Petango Store offers a full range of pet medications and pet specialty supplies, including heartworm brand names such as Heartgard, Advantage, Frontline, and K9. With up to 30% savings and free basic shipping, is the destination of choice for smart shoppers online.

Contact Information

  • Media Contact:
    Pethealth Inc.
    Susan Arts
    Vice President, Marketing
    (905) 842-2615