Why My Pet Needs An Exam For A Heartworm Preventative

Why Does My Pet Need an Exam to Get a Heartworm preventative?

Heartworm is a dangerous parasite that affects over 250,000 pets across the country. The worms themselves can grow to 12 inches in length, and reside within the chambers of your pet’s heart. Heartworm is particularly common in dogs, where symptoms include cough, lethargy, fatigue, loss of appetite, and weight loss. Left untreated, heartworm can impair your dog’s cardiac function and in severe cases may be fatal.

The good news is that heartworm is 100% preventable! So why does getting a heartworm preventative require pre-administration testing?

How Would My Pet Get Heartworm?

Heartworm is what’s called a vector-borne parasite. That means the parasite can only travel from host to host via an agent, such as a tick or mosquito. The way it works is simple. A mosquito bites a dog infected with heartworm, taking in a small amount of blood as well as the parasite larvae. When the mosquito later bites an uninfected animal, the heartworm larvae are introduced to the new host, transferring the infection. Heartworms, fortunately, can only be transmitted via mosquito, and preventatives are available through your vet.

What Pets Are at Greatest Risk for Heartworm?

Dogs and cats are both vulnerable to heartworm. Because heartworm is almost exclusively transmitted by mosquitoes, your pets should be tested if they live in an environment where mosquitoes are common. Remember, even indoor pets can get bitten, so get your pet tested before the spring warm-up.

What if My Pet Has Heartworms?

If your pet is already infected with heartworm, outcomes will depend on several factors, including the type of pet you have and the overall health of your pet.


Unfortunately there is no effective treatment for heartworm in cats. We may prescribe medications to ease inflammation and improve heart function, or we may recommend surgical removal of the parasites.


Treating heartworm in dogs is not without risk, and much depends on your dog’s general health. If your dog is diagnosed with heartworm, it will receive a course of medications lasting for several months. Complete resolution of the condition may take up to a year.

The American Heartworm Society recommends testing pets every 12 months for heartworm and giving your pet a heartworm preventative year-round. Have questions? Contact our staff, they’ll be glad to help!

The Value of Pre-Administration Testing

Heartworm preventatives are highly effective against the parasite, but they are not without risks to the host. To ensure that a heartworm preventative is safe for your pet, there are a few factors we like to check first.

  • Even if your pet has been given a heartworm preventative, we still test for heartworm. Why? Because administering a heartworm preventative to an animal already infected with the parasite can have dangerous effects.
No Medication is 100% Effective

  • The effectiveness of heartworm medication depends on timely dosing. Even one missed dose can leave your pet at risk for infection. Often you may not be aware that your pet has been infected, as heartworm is often silent in its early stages.
Maybe You Missed a Dose

  • At Tates Creek Animal Hospital, we use a test that not only scans for heartworm, but also tests for other vector-borne diseases such as Lyme Disease, Erlichiosis, and anastomosis to determine whether your pet has been exposed.
  • When heartworms die, the dead fragments are pushed deeper into the smaller vessels of your pet’s heart, where they can cause potentially dangerous, potentially lethal complications. A pre-administration exam and bloodwork allow our team to determine the extent of the infection before administering a preventative.
Heartworm Tests Are Not All Alike