Parasite Control

Heartworm Disease:
It's worse than you think.

All it takes is one mosquito bite.

Just one mosquito bite for a heartworm to fatally damage your pet slowly, silently and out of your sight. Here, you'll learn the scary truth about this microscopic menace and, most importantly, how you can prevent it from harming your pet.

Heartworm Life Cycle

  • A mosquito bites an infected animal and ingests young heartworm larvae.
  • Inside the mosquito, the young heartworm larvae grow into a viable parasite.
  • Heartworm enters a pet's bloodstream through a single mosquito bite.
  • It then migrates to its dream habitat: the pulmonary artery.
  • Over time, heartworms grow and lodge themselves inside the heart and surrounding blood vessels. There, they reproduce and release new young larvae into the pet's bloodstream.
  • Another mosquito comes along. It bites the infected pet, and the cycle starts over again.

Eventually, mature heartworms cause inflammation in the major blood vessels, gradually leading to:

  • Constricted blood flow
  • Weakened heart muscles
  • Obstructed lungs
  • Organ failures in the heart, kidneys and liver
Death can be sudden, or brought on slowly by one or more organ failures.
Heartworm symtops for dogs

In Dogs

Early Stage

  • Mild persistent cough
  • Reluctance to exercise
  • Fatigue after moderate activity
  • Decreased appetite
  • Weight loss

Late Stage

  • Swollen belly
  • Sudden labored breathing
  • Pale gums
  • Fainting
  • Sudden death
Heartworm symtops for cat

In Cats

Unfortunately, heartworm disease is harder to detect in cats, and regular blood tests don't always catch it. Regardless, keep an eye out for:

  • Vomiting
  • Rapid breathing
  • Weight loss

If heartworm disease does develop, Banfield veterinarians can effectively treat it. You should know, however, that the available treatments for heartworm disease are difficult, painful and expensive. So while effective treatment exists, it's an experience you definitely want to void.

Traetment for dos
Surgically removal treatment


Surgically remove the cluster of heartworms lodged inside the heart and surrounding blood vessels. This is a very risky and expensive procedure.

Multiple Injection care


Multiple injections of the compound immiticide, an arsenic-based product, are given to the infected dog to kill adult heartworms and stop them from reproducing. The treatment itself is quite effective, but risky.

Treatment for cats

There is no approved treatment in the United States for heartworm disease in cats, so their parasite prevention measures are especially crucial.

Did You Know?

  • In 2012, heartworm disease was most prevalent among dogs in Mississippi, Arkansas, Louisiana, Alabama and South Carolina.
  • The male heartworm can grow up to 6 inches. The female can grow up to 12 inches.
  • Canine Worm Stats: Life Span: 5 to 7 years, Adult Length: up to 12 inches, Quantity: up to 250.
  • Feline Worm Stats: Life Span: 2 to 3 years, Adult Length: 5 to 8 inches, Quantity: Less than 6.


Fortunately, this destructive parasite is far from indestructible. Heartworms can easily be stopped with simple, affordable, year-round preventive care.

  • Year-round heartworm preventives
  • Yearly heartworm tests

There are several types of heartworm prevention products to choose from:

  • Twice-A-Year Injectable
  • Monthly Topical Application
  • Monthly Tablets & Chewables

Bottom Line

Don't wait to protect your pet from heartworms.
Simple prevention now avoids difficult treatment later.

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