Heartworms: Prevention is the Best Medicine

April showers bring May flowers… and, unfortunately, the onset of heartworm season in much of the country. That’s why it’s National Heartworm Awareness Month. Heartworm can be fatal and it is very difficult – and expensive — to treat so prevention is always your best bet.  Here’s what you need to know.

What types of animals get heartworm?

Many mammals get heartworm including dogs and cats. The disease is rare in humans.  Note that heartworm susceptibility, diagnosis, and treatment are different for dogs and cats.

Where are heartworms prevalent?

Heartworm can be found throughout the U.S. but it’s more prevalent in the Midwest and Southeast because the parasite flourishes in tropical and subtropical climates.  Check this map to see how common it is in your area:


Heartworm Incidence Map Courtesy of Heartwormsociety.org

Heartworm Incidence Map Courtesy of the American Heartworm Society


How do pets get heartworms?

The parasitic nematode Dirofilaria immitis, commonly called heartworm, is transmitted via mosquitoes. When a mosquito infected with heartworm bites your pet it can transmit heartworm larvae into your pet’s bloodstream. Once inside your pet, the larvae continue to develop over the course of about six months. They make their way to the heart or lungs where they mature and reproduce. Adult worms live for years, can grow to more that 12 inches long and cause blockages in the heart and lungs and damage to arteries.

What are the symptoms of heartworm disease?

Often there are no obvious initial symptoms when your pet is infected with heartworm. Once the disease has progressed, dogs may begin to cough, experience shortness of breath, and be unwilling to exercise. Symptoms in cats are non-specific – like coughing or rapid breathing — and are often mistaken for other medical problems. Some pets show no symptoms until they collapse or faint due to “caval syndrome,” at which stage the body is so infected that treatment and recovery are unlikely.

Why is heartworm prevention so important?

Once a pet has been bitten by an infected mosquito it takes up to six months for the heartworms to show up on tests. By then damage has been done and treatment regimens are costly, complicated and aren’t always effective. Your best bet is to prevent this disease rather than attempt to treat it.

We stock many heartworm preventative treatments for dogs and cats.  Choose from monthly oral medications or topical treatments — both types are effective, convenient, and affordable. Talk to your veterinarian about which treatment is best for your pet and your area.

Want to learn more about heartworm and how to prevent it? Listen to Dr Rubin’s short podcast presented by the American Heartworm Society.

Here’s to a happy, healthy spring for your pet!


Give Heartworm Preventatives Year Round

Photo by Brian KingHeartworm disease, a parasitic infection spread by mosquitoes, can affect any dog. They might be young, old, male, female, indoor, outdoor, a city and/or country pet, but no pooch is immune. A common disease, it is naturally more prevalent in areas with a large mosquito population.

Heartworms have an extremely long life cycle. Living within a dog’s heart and/or surrounding vessels, they actually grow anywhere from four inches to a foot long, reaching maturity twelve months post infection. These parasites can survive for as long as five to seven years. Offspring of adult heartworms also circulate within the infected animal’s blood. Quite often, a dog infected with heartworms will be asymptomatic in early stages of the disease.

Stressing a dog’s heart by restricting its blood flow as well as damaging other internal organs, heartworms are considered the most dangerous type of parasites that dogs can contract. A dog’s heart can become enlarged and weakened, leading to congestive heart failure which can be fatal.

Other common, less serious, parasitic infections dogs often contract include hookworms, tapeworms and roundworms.

Signs and Symptoms of heartworm disease in dogs include:

  • Dog has problems breathing.
  • Dog develops a cough.
  • Dog tires more quickly than usual.
  • Dog is listless.
  • Dog appears to be losing weight.
  • Dog has a distended abdomen.
  • Dog has a rough coat.

**Note**: Prompt detection and treatment avoid needless suffering for your dog.

If your dog has developed any of the above heartworm disease symptoms, here are steps that should be taken for accurate diagnosis and appropriate treatment:

  1. Blood Testing: Blood serum tests can determine the presence of heartworms in your dog’s bloodstream.
  2. Radiology and/or Ultrasound: In cases of more advanced stages of heartworm, x-rays and/or ultrasound are utilized to detect this parasitic infection.
  3. Medical Evaluation: Your dog’s veterinarian will perform a thorough medical examination to ascertain the progress of the disease.
  4. Follow-up Medication Visits: A series of follow-up visits will be needed in order for the doctor to administer several injections of strong anti-parasitic medication.
  5. Monitoring: Close monitoring of the animal is required, after the initial treatment, including hospitalization for a few days to keep the dog quiet.
  6. Surgery: In very severe cases, surgery may be required. This is very dangerous for the dog as well as expensive for the you.
  7. Confinement: Dead heartworms can cause strokes. Hence, the dog will need to be kept confined to a small room (or large crate) and not allowed to exercise for a few months after treatment is complete.

While you may find the above steps alarming, the good news is that the majority of dogs with heartworm disease can be successfully cured. This is typically accomplished with medications capable of killing both the adult parasites and their offspring.

However, there is no better cure than a proactive heartworm preventative! Heartworm prevention is considerably safer for your dog as well as much less expensive for you!

When given regularly and properly, heartworm preventative medications are very effective. They can successfully keep your beloved pet from contracting serious heartworm disease as well as control other types of parasitic infections (i.e. hookworm, roundworm, etc depending on medication).

It is essential your pet be kept on a monthly heartworm preventative regiment. Your dog still needs to be checked periodically to make sure the prescribed medication is providing adequate protection. 

One very effective heartworm product is Tri-Heart Plus (ivermectin/pyrantel). This combination medication is available in three different dosages of flavoured chewable tablets, depending on the size of your dog. Click here to read about additional pet meds for heartworm prevention or browse through VetRxDirect’s full selection of related treatments.

So do your part to keep your pup healthy and happy year-round by keeping heartworms at bay!