Why Your Dog Should Take Monthly Heartworm Prevention Medication

Mosquitoes can carry heartworm larvae, and a bite from an infected insect could mean heartworm disease — and permanent damage to the heart, lungs, and blood vessels — for your dog down the line. A dog might not show any signs of infection, or he or she might cough, be lethargic, or lose weight inexplicably. Treatment usually involves a series of injections. The good news is that by following a heartworm prevention medicine regimen, it can be completely prevented.

Heartworms are spread through the bite of a mosquito, and dogs increase the risk of infection for other dogs, cats and other animals. When a mosquito bites an infected dog it draws blood that contains immature heartworms, called microfilariae  These microfilariae mature inside the mosquito to become infective larvae. When the mosquito eventually bites another dog or a cat, the larvae enter the new host. In dogs, these larvae often mature to become adult heartworms, which produce more microfilariae and continue the heartworm’s life cycle.

Heartworm disease can cause a variety of medical problems affecting the lungs, heart, liver, and/or kidneys. Severe complications can lead to death. Although a safe and effective treatment is available, treatment can cost upwards of $1000, depending on how long the dog has been infected and how severe the infection is.

A simple blood test can detect most cases of heartworms and should be performed annually.  At Markham Animal Clinic, our annual blood test for dogs includes a heartworm test, screen for tick-borne disease such as Lyme disease, a complete blood count and blood tests for kidney and liver function, for little more than a heartworm test alone.

Despite the fact that heartworm disease is virtually 100 percent preventable, many dogs are diagnosed with it each year. The American Heartworm Society (AHS) estimates that one million dogs in the United States have heartworm disease today, and that this number may be rising.

Some dogs may show no signs of infection. However, depending on the number of worms and the duration of infection, dogs may begin to show cough, lethargy, exercise intolerance and weight loss.

If infection is detected early enough, heartworm disease can be treated before permanent damage to the heart, lungs, and/or blood vessels occurs. However, if the infection has been present for a long time or consists of a large number of worms, the risk of complications increases. In these cases, treatment can be more expensive and complicated and dogs may take many months to recover from the infection.

Fortunately, safe, easy-to-give, effective medications are available to prevent heartworm disease. Most heartworm preventive medications are administered as monthly oral medications. These monthly preventives also prevent intestinal worms which can be transmitted to you and your family. Prevention is convenient and inexpensive compared to the dangers of the disease for dogs.