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Facts About Heartworms

Heartworm disease in dogs is very common in the Southern United States and anywhere where mosquitoes live. To that end, here are the facts about heartworms so that you can protect your pet.

What exactly are heartworms?

Heartworms are worms that live and grow in the heart of an infected dog. They damage the heart’s ability to pump blood to the rest of the body. Likewise, they can cause lung disease, heart failure and other organ damage. Ultimately, if left untreated, heartworms are deadly!

How do dogs get heartworm disease?

Heartworms are passed from dog to dog by mosquitos. For example, when a mosquito bites a dog that already has heartworms, that mosquito then carries the disease.  As a result, when that mosquito bites another dog, it transmits the heartworms to that dog. In fact, one mosquito bite is all it takes to spread heartworm disease in dogs!

heartworm life cycle illustration

How do I know if my dog has heartworms?

The only way to know is to visit your veterinarian for a heartworm test.  In fact, your dog has to have a negative heartworm test to receive heartworm preventative.  Therefore, ask your veterinarian to perform one every year.  

My dog looks healthy. Does that mean that he doesn’t have heartworms?

It can be hard to identify heartworm disease in dogs. For instance, dogs who have heartworms might now show any physical symptoms until they’ve had them a long time. Physical symptoms can include difficulty breathing when running or playing, coughing up blood and even a very large abdomen. 

If I buy dewormer medicine at the store and give it to my dog, will that prevent or kill heartworms?

No. Dewormer medicine kills intestinal parasites such as hookworms and roundworms. But they do not kill heartworms.  In fact, heartworms live in the blood vessels and not the intestines, so dewormers have no effect on them. Heartworm preventative is the only medicine that can prevent heartworms. Many heartworm preventatives also kill intestinal parasites.

How can I prevent my dog from getting heartworms?

The only way to prevent heartworms is by using heartworm prevention medicine. The most common is a treat-like chewable that you give your dog monthly. You can purchase heartworm preventative through a veterinarian. Addtionally, you can purchase it online at pet stores like Chewy or Petco with a prescription from your vet. The medicine costs from $10-$30 a month.  Also, some brands prevent fleas and ticks too.  Be sure to keep your dog on prevention throughout the year to keep them safe.

Can heartworms be passed to my other dogs?

Not quite. Because heartworms are carried and transmitted by mosquitoes, one dog cannot pass it to another. Further, heartworms are not contagious and can only be passed by mosquitoes.

My dog is always indoors. Does that mean that he is safe from getting heartworms?

Even if your dog never goes outside, a mosquito can enter your house and bite your dog. Censequently, there is no guarantee of protection — even if your dog is always indoors!

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