Chocolate labarador retriever sitting in grass.

It is absolutely reasonable to question every vaccination, medication, and preventive method recommended for your companion animal. Indeed, that’s the very essence of responsible pet ownership. Heartworm disease in dogs has the potential to cause severe lung disease, heart failure, organ damage, and can even be fatal. Together, we can ensure your dog has every possible protection against heartworm-carrying mosquitos and other parasites.

Don’t Look Away

Microscopic worms deposited in the bloodstream by an infected mosquito sounds like something from a science fiction/horror movie, but the truth is scarier than fiction. Dogs are considered ideal hosts for these parasitic worms known as Dirofilaria immitis, meaning the conditions inside a dog’s body are hospitable to the worms. This internal environment allows the worms to mature, mate, and produce offspring inside the heart, lungs, and surrounding blood vessels. 

Shocking and Terrible

Mosquitoes are incredibly stealthy and often pass unnoticed until well after they initiate a bite. Even a quick blood meal can be enough time for a mosquito to pass the microscopic worms into a dog’s bloodstream. A newly infected dog may not show symptoms of heartworm disease for several months. By then, the worms have matured, released offspring, and completed the life cycle. 

Worm Burden

Heartworms can live between 5-7 years in an ideal host. By then, they can measure between 6-12 inches in length, resembling cooked spaghetti noodles. The average “worm burden,” or number of “healthy” adult worms, is 15 worms. That said, there have been cases of a worm burden being over 200!

Heartworm Disease in Dogs

Symptoms may be harder to detect in dogs with low worm counts, but can be obvious in dogs that have a lot of worms, have been infected for a length of time, or previously enjoyed strenuous activities. Owners may start to notice the following red flags:

  • Coughing
  • Fatigue (even after an easy activity)
  • Weak-looking appearance

These symptoms require immediate veterinary examination and diagnostic testing. If left untreated, heartworm disease in dogs will progress to the point of irreversible damage to the heart, kidneys, liver, and lungs. Heartworm disease can be fatal in dogs. 

Testing and Treatment

Blood tests can detect the presence of adult female heartworms, as well as microfilariae (immature worms), given around 6 months after a bite, to determine if adult worms are reproducing inside the host. Testing should always be completed prior to starting (or re-starting) a dog on their heartworm preventive medication. A preventive medication can actually cause anaphylactic shock or death in a heartworm-positive dog as the worms suddenly die off inside them.

Heartworm disease can be treated in dogs, but with numerous medications, X-rays, and other diagnostics, it is often an arduous and expensive process. Surgical removal of large worms is another option, but has its own set of risks. 

Prevention Is the Key

Most prescription heartworm preventive medications are given orally or topically, once a month. There is also an effective injection, administered in our office every 6-12 months. It is recommended that dogs receive permanent, year-round heartworm prevention medication to reduce the chance of contracting this terrible disease. Remember, all it takes is one small mosquito bite to rock the boat of your dog’s health and wellness.

As always, please reach out to us at (818) 614-9929 with any questions or concerns. Shiloh Mobile Veterinary Hospital is always here for you!