It’s been more than 150 years since a scientist discovered the heartworm parasite of dogs and more than 80 years since the parasite was found in cats. We now know that coyotes, foxes and ferrets can be affected. Each year, hundreds of thousands of dogs and cats are diagnosed with this dreaded worm, and it is estimated that North American cases are actually in the millions. In all this time, why have we not found a way to combat and stop this plague?
Spread by mosquitoes, the heartworm parasite can grow close to 2 feet long and takes up physical space in the heart’s chambers and pulmonary artery. This means that the pet’s heart must work harder to push the same amount of blood out to the body. Early signs of this disease include fatigue and exercise intolerance, but later signs can include coughing, fluid accumulation in the lungs or abdomen and death.
For cats, the heartworm larvae prefer the lungs and can cause vomiting, asthma-like symptoms and even sudden death in some cases.
Not only is the pet harmed, but the owner is affected, as well. Treatment of a pet for adult heartworm can cost well over $1,000 to $3,000 depending on the size of the pet and the degree of damage to the lungs and heart. The treatment used is an arsenic compound that can have harmful side effects. Sudden, unexpected loss of a pet due to the parasite or the adulticide is traumatic for the family.
For a period of time in 2011, the one drug used as a heartworm adulticide was not being manufactured, and veterinarians did not have access to the one drug available to treat positive heartworm cases. So, even if one had the means, there was not any treatment available to kill the adults. Thankfully, the medicine is available again.