Canine Heartworm Disease

This disease is found in all areas of the United States and parts of Canada since the early 1970s.

Areas that are heavily populated by mosquitos tend to have higher incidences of heartworm disease. Although primarily it infects dogs, cats and ferrets are also at risk.

effects of canine heartworm disease
Healthy Heart on the Left-Infected Heart on the Right


One mosquito bite can lead to the death of a pet. Once a pet has been bitten by an infected mosquito, the heartworm lives in the blood of a dog’s heart and adjacent blood vessels.

The adult heartworms produce offspring, which are called microfilariae.

These circulate throughout the animal’s blood. This is transmitted when a mosquito bites an infected pet, sucks out blood containing the microfilariae or offspring.

About two weeks in the mosquito, this becomes infected larvae and when the mosquito bites another pet, it infects that animal.

Thanks to veterinary research, there are now medications and procedures that have improved the treatment of this disease.

Like many other diseases, early detection and treatment can lead to a successful cure.

Diagnostic tests and medications to prevent heartworm disease from occurring at all are inexpensive and available from your veterinarian.

However, before your dog can be placed on preventative medications, your veterinarian will request a heartworm screening test.

This is in order to detect the presence of heartworm disease that may already be infecting your pet. Without knowing it, your dog may already be infected.

Therefore it is vital that dogs six months and older have a blood test prior to starting them on the monthly preventative.

Severe or fatal reactions may occur if preventatives are given to dogs that have heartworm disease. If the dog has been to a known heartworm problem area, your vet may recommend additional tests.

Other testing methods may include a complete blood count (CBC), organ function profile, or x-rays. If the disease is detected, these tests can also help determine the degree of infection.

Symptoms of heartworm disease include:

  • Difficulty breathing
  • Coughing
  • Tires Easily
  • Listlessness
  • Weight Loss
  • Rough Hair Loss

Many cases have advanced systems. Some pets don’t appear to have symptoms early on and others do.

Left untreated heartworm disease can lead to congestive heart failure and death. Treatment for heartworm disease can be risky and expensive.

That is why year-round prevention is so very important. If a pet does get heartworm disease and survives-it is not immune and will still need to be placed on a monthly preventative.

It needs to be done, better to do it now before your pet gets sick!