On a quintessential summer day, you venture outdoors with your dog to enjoy nature’s beauty. Mosquitoes, although uninvited, likely will join you. Mosquitoes may be mere nuisances to us, but for our canine companions, they can be much more. They have the potential to infect dogs with heartworms and cause heartworm disease. What are heartworms? Unfortunately, they are exactly as they sound. 

Heartworm disease—exactly as it sounds

Heartworm-infected mosquitoes can be found almost anywhere in the U.S. A heartworm-infected mosquito that bites your dog can transmit heartworms in the larval stage, called microfilaria, into the bloodstream, where they will mature into adult heartworms in about six months. Adult heartworms, which are about 12 inches long and look like spaghetti, reside in your dog’s heart, major blood vessels, and lungs, and cause infection with clinical signs such as breathing difficulty, coughing, and exercise intolerance. Severe infections can cause heart failure. 

How to tell if your pet has heartworm disease

Our veterinary team can screen for heartworm disease in your pet with a simple blood test that can identify whether she is carrying a protein produced by female heartworms that is found in heartworm-infected dogs, but not healthy dogs.

Annual heartworm testing is essential for your pet’s good health, and a prevention plan can only be implemented once she is given a negative test result. If prevention is instituted when she has adult heartworms living in her body, the consequences are dramatic. Dead worms can be carried en masse through her body, and the clumps can cause a blockage or cut off blood flow, and cause serious illness.

How heartworm prevention works in your pet

Heartworm prevention includes regularly medicating your pet to kill microfilaria before they can mature into adult heartworms. The medication is available in three forms: 

  • Tablet — A flavored chewable tablet, given monthly, is the most commonly used heartworm preventive.
  • Topical — Medication can be applied to your pet’s skin monthly.
  • Injectable — We can use an injectable heartworm preventive that only needs to be administered every six months to dogs.

When choosing a heartworm preventive for your pet, consider that remembering oral or topical medication each month may be more difficult than scheduling an injection twice a year for your dog. If you miss a single dose—and you would not be alone—you should call us, because your pet’s health may be compromised, and she may need additional testing.

Our veterinary team can help you decide the best form of heartworm prevention for your pet.

Heartworm disease in cats

Since our discussion has focused on dogs, you may be wondering if cats can be affected by heartworm disease. The short answer is: Yes. There are several significant differences between heartworm disease in dogs and cats, however. Cats can be bitten by an infected mosquito, with transmission of several microscopic larval worms, but cats are considered a dead-end host for the worms, as they prefer to live and replicate in dogs. Although heartworms can survive in the cat’s body, they cannot reproduce to cause a fulminant infection. But, this does not mean that heartworms are not dangerous to your cat. The few worms transmitted to a cat can live for several years, and incite significant inflammation in its lungs. Cats with heartworm disease may cough, wheeze, or vomit, but many show no signs. It is also possible for infected cats to suddenly collapse or die without showing prior clinical signs. 

Many cat owners assume their indoor cats are safe from heartworms, since they do not venture out into mosquito territory.  Mosquitoes commonly fly into homes, however, drawn by porch lights and the possibility of their next meal. Indoor and outdoor cats should receive regular heartworm prevention to keep them safe from this deadly parasite. Ask our veterinary team to help you select an appropriate product to protect your feline friend. 

A word of warning about alternative heartworm treatments for your pet

The heartworm preventives that our veterinary team recommend have been rigorously tested for efficacy and safety. You may see alternative treatments on the internet that may sound interesting, but they can be dangerous for your pet, and we strongly advise against them. Feeding your pet beer, tobacco, or garlic, for example, is not only inappropriate and ineffective in preventing or treating heartworm disease, but also can make your pet ill.

At Medina Veterinary Clinic, we believe that heartworm-disease prevention is the best medicine. If you have heartworm-related questions, or need help choosing the best preventive form for your pet, schedule an appointment with our team.