Pesky Parasites: Heartworms and Mosquitoes

What are heartworms?

Heartworms are internal parasites that live in the heart, lungs, and large blood vessels of the host-animal. They are most commonly found in dogs, but cats can have them too. Heartworm disease is one of the deadliest diseases that can affect our pets, but luckily it is completely preventable.

How are they transmitted?

Heartworms are transmitted to an animal by mosquitoes. Feeding mosquitoes act as carriers of the disease, depositing the heartworm larvae onto the unsuspecting animal. Once mature, the adult larvae migrate to the chambers of the heart, lungs, and large blood vessels of the lungs where they mate and reproduce (NOTE: worms in cats rarely survive to adulthood so reproduction typically does not occur in cats).

Cats vs. Dogs

Heartworm disease in cats is much different that heartworm disease in dogs. Dogs are considered a natural host for heartworms. Once deposited onto the animal by a mosquito, the heartworms can thrive and multiply in a dog’s organs. In contrast, heartworm larvae rarely reach the adult stage in cats. This major distinction means that the symptoms, prevention methods, and treatment of heartworm disease are different for dogs and cats.

Dog Symptoms

A heartworm infection can affect all the major organs of a dog—the heart, lung, kidneys, and liver. Since the disease can affect virtually any major organ, the symptoms are quite varied. The most common are:

  • Decreased appetite
  • Weight loss
  • Mild persistent cough
  • Fatigue
  • Swollen belly
  • Lethargy
  • Labored breathing
  • Pale gums
  • Dark bloody urine

Left untreated, most dogs cannot survive heartworm disease. If your dog exhibits any of the symptoms above please contact your vet immediately. Heartworm is a progressive disease, the earlier it is detected, the better chances your dog will recover.

Cat Symptoms

Most heartworms in cats do not survive to adult stage. However, even the immature worms can affect a cat’s health. Cats with immature worms can suffer from a condition called heartworm associated respiratory disease (HARD). The most common symptoms in cats include:

  • Coughing
  • Vomiting
  • Lack of appetite
  • Asthma-like attacks
  • Swollen belly
  • Fainting
  • Seizures
  • Difficulty walking or standing

Even though cats are less likely to have heartworms, you should contact your vet if your cat exhibits any of the symptoms above. Left untreated, cats can get respiratory disease and even die.

How do I prevent my pet from getting heartworms?

Heartworm has been found in all 50 states. And unlike fleas and ticks who have a “season”, heartworm and mosquitoes have no definite season. This means that our pets our always at risk—even those that live primarily indoors. Fortunately, heartworm is 100% preventable. Preventative medication (usually a monthly oral table) can only be prescribed by a vet. After testing your pet for heartworm, your vet can recommend the most effective medication for your pet. If your pet tests positive for heartworm (blood test), your vet can recommend treatment options.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s