Mosquitoes swarm these days when I work in the garden. I worry about dog heartworms with the increase of these buggy pests. Are your dogs protected? Do you know how dogs get heartworm? Read on!
I hate mosquitos not only because they’re itchy aggravation, but these nasty vampires spread deadly dog heartworms. That can make your dog sick or worse—it could kill her. Dogs are the natural host–but they also can affect cats–and heartworms have been a problem at least since 1922 when they were first discovered. Today heartworms are found all over the world.
The heartworm Dirofilaria immitis belongs to a group of parasites called filarids, and is a type of roundworm. They live in the right heart chambers and pulmonary arteries—the lungs—of infected dogs. As you can imagine, lungs and heart filled with worms can damage and interfere with normal organ function. You won’t be able to tell if your puppy has heartworms. You can’t see them the way you can fleas or ticks. And your dog won’t even act sick until she’s been infected for quite a while.

Hunting dogs that spend lots of time outdoors are at highest risk.
DOG HEARTWORMS
Despite the availability of effective and easy to use heartworm preventive options, the disease appears to be on the rise. In just two years, from 2013-2015, there was a 166 percent increase in reported positive heartworm cases, according to the Companion Animal Parasite Council (CAPC). Additionally, the American Heartworm Society (AHS) has tracked the geographic spread of heartworm disease to all 50 states and its increased prevalence in several regions of the country.
So what’s a pet parent to do?
UPDATE ABOUT DOG HEARTWORMS & MOSQUITOES
A groundbreaking study by John McCall, MS, PhD addresses this concern. He investigated the effectiveness of stopping heartworm disease at the buggy transmission source. His research shows that a multi-modal approach (adding mosquito repellents and insecticides alongside standard heartworm preventive protocols), offers even better protection for our dogs.
I first reported on this study back in Fall 2016. The study, sponsored by CEVA, explored the efficacy of a new “Double Defense” protocol. John McCall is a professor emeritus in the Department of Infectious Diseases at the University of Georgia College of Veterinary Medicine. After fighting heartworm the same way for decades, McCall says it’s time for a new approach that includes fighting the mosquito as well as the heartworm.
PREVENTING VS TREATING HEARTWORMS
Preventives that address heartworms are one important part of canine health care. But until recently, preventing the vector (mosquito) hasn’t gotten the attention it deserves, according to Byron Blagburn, MS, PhD, DAVCM, a professor of parasitology,, researcher, and author of the mosquito control guidelines.
The Companion Animal Parasite Council (CAPC) included more information on how to control mosquitoes, adding science-based evidence to these guidelines on mosquito control. New recommendations include choosing heartworm and parasite prevention products that also address the mosquito menace. Several canine products are available, and you should consult with your veterinarian for the best choices for your individual dogs and circumstances.
According to the Heartworm Incidence Survey from the American Heartworm Society, the average number of dogs diagnosed per clinic in 2016 rose by 21.7 percent over 2013 numbers (date of the last survey). AHS president and veterinarian Dr. Christopher Rehm says that the distribution of cases hasn’t dramatically changed, 24% of respondents said the average number of positive dogs has increased since 2013.
2021 Heartworm Predictions–Keep Dogs Safe!
LEARN MORE ABOUT DOG HEARTWORMS
Please ask YOUR veterinarian about how you can best protect your dogs from mosquitoes and dog heartworms. Learn more about Dr. McCall’s CEVA-funded study in this short video.
Several years ago, I interviewed Dr. Wallace Graham about prevention, treatment and more in my Pet Peeves radio show. Much of this information is still valid, so find out more about how to keep cats and dogs safe from heartworm disease in PET PEEVES, HEART-TO-HEART ABOUT HEARTWORMS.
For more about parasite prevention, refer to this post.
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Amy Shojai, CABC is a certified cat & dog behavior consultant, a consultant to the pet industry, and the award-winning author of 35+ pet-centric books and Thrillers with Bite! Oh, and she loves bling!
Here Here on heartworm prevention. I bred and showed dogs for over 40 years tho my last litter was some years ago I have never stopped preaching about the issues of mosquitoes and heartworms. In my “puppy packs” given with each new pup sold, the owners received not one, not two but at least three articles or brochures on heartworm prevention. I found the drug companies producing the meds were happy to send you brochures to hand out and I found them all very good. In fact, one buyer took their other dog in for a checkup at same time they took the new pup in for vet check and found their other dog had heartworm and he had to go thru the full treatment. So thanks for you continued information. My dogs were on prevention year round since they traveled to dog shows in a wide range of locations and were exposed to dogs from all over the country.
Mine are on year round prevention, too.
Thank you from KoKo and me!
Glad it helps!
Hi Amy, great article. Our Golden Retriever rescue, Annabelle (we lost her in October of 2020 from cancer), was rescued from Baton Rouge LA. She came up to New Hampshire with a negative heartworm test. A few months later, she texted positive. The heartworm were quite big, so the veterinarian felt that she came up with them. The vet said that because we started her on heartworm medication right away, that is why she didn’t show up positive for those few months. The heartworm medication possibly saved her life. She had to stay in the hospital 2 nights so they could monitor . The process was done twice and it was between $2-3,000. It wasn’t any easier to leave her for the second dose of drugs.
Making sure that your dog gets his heartworm medication every month is far easier emotionally and monetary. No knowing if they caught the heartworm in time before they caused too much damage to your dogs heart is very, very stressful. So I plead with everyone to not only give your dog heartworm medication monthly but provide a good flea and tick medication as well.
Hi Wanda,
I’m so sorry you lost Wanda–but glad her heartworm treatment proved successful. Your story should be a wake-up call to all pet lovers! Thanks so much for sharing.