Heartworm Disease FAQ’s

With April being Heartworm Awareness Month, we’d like to take the time to answer any frequently asked questions regarding this disease and how you can help.

Yes, heartworm disease is serious in dogs, especially if it is left untreated. But it is also easy to prevent and is treatable. Dogs treated for heartworm — especially if is it caught early — can go on to live completely normal, wonderful lives.

Let’s get started:

What exactly is heartworm disease?

Heartworm disease is a parasitic worm that inhabits the heart, lungs and associated major vessels in both dogs and cats. Dogs are considered a primary host, which means that heartworms can grow and reproduce in an infected animal. In fact, hundreds of worms can inhabit the heart and lungs of a single dog.

How do pets get heartworms?

Heartworm disease is spread by mosquitoes; the baby heartworms, called microfilaria, are found in the bloodstream of infected dogs. Mosquitoes pick up the larvae of the heartworms when feeding and then transfer them to other animals. The larvae then grow and mature into adult worms.

What are the symptoms of heartworm disease in dogs?

The most common signs in dogs are coughing, exercise intolerance (or getting tired easily with exertion), collapse or fainting episodes, decreased appetite and weight loss. Many dogs, however, show no signs at all early on.

How do you test a dog for heartworms?

Early detection is key to treating the disease successfully. Because many dogs show no signs during early infection, a positive test can guide early treatment and help to avoid potentially fatal complications. The test involves collecting a small blood sample, which can either be analyzed at the veterinarian’s office or sent out to a diagnostic lab. The results are usually acquired rapidly, within a few minutes if run in-house or in a couple of days if sent out.

Because of the worm life stage that the test detects, it will take a dog about six months to show up positive on a test from the day he was infected by the mosquito. For this reason, for dogs not previously on prevention, it is recommended that the test be done immediately, and then again in 6 months.

I found out my pet has heartworms, now what?

If your dog tests positive for heartworm disease, there are several steps to treatment. Your veterinarian may want to perform additional testing to confirm the diagnosis and to look for evidence of infection on blood work or X-rays. This can help to determine the likelihood of complications occurring with treatment. (Despite potential treatment risks, however, heartworm disease will most certainly prove to be fatal if left untreated. That’s why early detection is so important.)

Treatment at JHS:

  • 30 days of an antibiotic called doxycycline, used to weaken pre-existing heartworms
  • a 30-day rest period
  • 2 injections with melarsomine, an agent that will kill the adult heartworms and an overnight stay at the hospital

During treatment, it is imperative that your dog’s activity be restricted. Increased activity before and during treatment (and for up to six weeks afterward) has been associated with an increased risk of complications. What this means is that the dog should go on leash walks only, with kennel confinement at all other times. Sedatives can be used to keep a dog calm while undergoing treatment; your veterinarian can help determine if this is necessary.

Are heartworms contagious to other animals/pets?

The only way heartworm spreads from host to host is if a mosquito bites a dog with heartworms and then moves on and bites another dog. Even under this circumstnace, the microfilariae can only be spread if conditions are just right.

*Humans cannot get heartworm

How can I prevent my pets from heartworms?

There are several options for preventing heartworms in dogs, all of which require a veterinarian’s prescription. A monthly chewable tablet is usually all it takes. This product works by killing off heartworm microfilaria in the pre-larval stage before they can grow into adult worms. Bonus: Some heartworm preventives contain other ingredients that also help prevent roundworm, hookworm and parasites such as fleas and ticks.

How does JHS help dogs with heartworm disease?

JHS provides compassionate care to nearly 9,000 animals each year, some of which come to JHS as heartworm positive. JHS will cover the entire cost of heartworm treatment for each dog, averaging to a total of $50,000 each year in heartworm treatment alone.

JHS will also place all dogs on heartworm preventatives during their time at the shelter to ensure each pet is protected.

How can I help homeless pets with heartworms?

Do you still have questions? Feel free to reach out to us any time! Email us your questions or concerns at info@jaxhumane.org.