A colleague and I were volunteering as the emergency vets for the Atlanta Dog Jog held in Piedmont Park by the local veterinary association. Owners and their dogs were all enjoying beautiful weather and a fun walk/jog/run in the park for charity. By early afternoon, we had had an uneventful shift at the emergency booth and the day was wrapping up happily.
Then we saw him: a handsome Golden Retriever walking up to us with his owner. The dog had a cough and a trickle of blood coming from his nose.
Owner: I think my dog has bumped into something and gotten a bloody nose.
My colleague: When did this cough start?
Owner: While we were running just now.
Me: Do you have him on heartworm prevention?
Owner: (Long silence) Uh, is that the monthly chewable, kinda block shaped?
My colleague: Yes.
Owner: Uh, yeh, uh, I have that.
Me: Are you giving it?
Owner: (Long silence) Uh… no.
My colleague and I just looked at each other as our hearts sank. This dog likely had heartworm disease even though the once-a month chewable preventative was sitting at home on his owner’s shelves. Doing nothing.
We urged the man to take his dog to an animal emergency center right away and to keep his dog EXTREMELY quiet in the meantime. He demurred, wanting instead to wait until Monday morning to see his own vet. We understood his reluctance to go somewhere unknown and expensive, but we tried to impress on his that his dog really was facing a life threatening emergency. We recognized the signs that this dog was reacting to the 6 to 12 inch worms living in his heart and that any more activity might be all he needed to die from them. All we could do was present our case to him and hope for the best. I never learned what happened to that handsome Golden.
The statistics about heartworm disease paint an equally saddening picture. According to the American Heartworm Society, the reporting veterinary clinics in the metro Atlanta area each saw over 50 cases of heartworm disease. Some clinics diagnosed it more than one hundred times that year alone. Even more saddening, 65% of all dogs who go to the vet go home without heartworm prevention. One researcher found that many dogs diagnosed with heartworm disease had prevention available at home, but their owners had forgotten to give it, just like the Golden Retriever I met so many years ago.
What Is Heartworm?*
A heartworm is a parasitic worm (Dirofilaria immitis) that lives in the heart and pulmonary arteries of an infected animal. The worms travel through the bloodstream—harming arteries and vital organs as they go—ultimately completing their journey to the vessels of the lung and the heart chamber about six months after the initial infection. Several hundred worms can live in one dog for five to seven years. Heartworm disease is serious, and can be fatal.
What Causes Heartworm?
Heartworms are transmitted from animal to animal by mosquitoes. The lifecycle of the heartworm is complex. An animal must carry at least two heartworms (a male and a female) in order for female heartworms to reproduce. Females produce babies, called “microfilariae,” which are shed into an animal’s bloodstream but are not capable of directly causing heartworm without first passing through a mosquito. The microfilariae must be taken up by biting mosquitoes, and transform into infective larvae over a two-week period inside the insect. When the mosquito next bites a susceptible animal, the infective larvae enter the tissues and begin a migration into the blood vessels.
Heartworms enter an animal’s bloodstream as tiny, invisible larvae, but can reach lengths of more than twelve inches at maturity.
How Can Heartworm Be Prevented?
The good news is that heartworm is easy preventable with an inexpensive, chewable pill available with a vet’s prescription. The pills—highly palatable to most dogs—are usually administered monthly and manufactured by several companies. The pills can be given to dogs under 6 months of age without a blood test, but older animals must be screened for the disease prior to starting medication. You can opt to give your dog a pill only during mosquito season (spring through first frost), but the most recent recommendation from the American Heartworm Society is to keep giving them all year—not only does this avoid errors, but many of the products also prevent other intestinal parasites. There are also topical products available that you can apply to the skin.
So go to your drug cabinet now. Right now. Do you have heartworm prevention for your dog on hand? When did you last give it? If it has been more than a month, call your vet now, right now, and ask what you should do. Depending on the circumstances he may tell you simply to get back on your preventative immediately or she may want you to come in for a test.
If you don’t have a regular veterinarian, we urge to begin a relationship with one. Call now, right now, and make an appointment for an exam and a simple blood test to be sure your dog hasn’t gotten heartworms. Then you can start protecting your beloved family member from this deadly and completely preventable disease.
*The excerpt above regarding the definition, causes and prevention of heartworm was taken from the ASPCA’s website. Visit https://www.aspca.org/pet-care/dog-care/heartworm to read the full article.
