April is Heartworm Awareness Month, a time dedicated to educating pet owners about one of the most serious and preventable threats to our dogs’ health. As temperatures rise and mosquito activity ramps up across the country, the risk of heartworm disease increases. That’s why April serves as a timely reminder: prevention starts before peak mosquito season hits.
As a pet owner, understanding what heartworms are, how they spread, and how to protect your dog is essential to keeping your furry friend happy and healthy year-round.
What Are Heartworms?
Heartworms are parasitic worms that can live in many animals, including dogs, and move into the heart, lungs, and blood vessels. Over time, they can grow up to a foot long and cause severe damage to a dog’s cardiovascular system.
Left untreated, heartworm disease can lead to lung disease, heart failure, organ damage, and even death. The scary part? It all starts with something as small and common as a mosquito bite.
How Do Dogs Get Heartworms?
Heartworms are transmitted through the bite of an infected mosquito, making even a single bite a potential risk. When a mosquito feeds on an infected animal, such as a fox, wolf, or another dog, it picks up microscopic heartworm larvae. If that same mosquito then bites your dog, it can pass those larvae into your dog’s bloodstream. Over the course of several months, the larvae grow and mature, eventually settling in the heart, lungs, and surrounding blood vessels where they begin to cause damage. Because mosquitoes are widespread and difficult to avoid, any dog, regardless of how often it goes outside, can be at risk for heartworm disease.
Where Are Heartworms Most Prevalent?
Heartworm disease has been diagnosed in all 50 states, but it’s most prevalent in warm, humid regions where mosquitoes thrive. However, the risk isn’t limited to those areas. Cases are on the rise even in regions that were once considered low-risk, making prevention important no matter where you live.
Is There a “Heartworm Season”?
Heartworms are closely tied to mosquito activity, which peaks in warmer months. However, milder winters and changing climates mean mosquitoes can survive longer than ever. The bottom line is: Heartworm prevention should be given year-round, not just in spring and summer.
Does My Dog Have Heartworms?
One of the most challenging aspects of heartworm disease is that symptoms often don’t appear until the disease has progressed. By the time you start to notice signs, the heartworms have typically matured into adult worms and reproduced, leading to a growing population of worms in the heart and lungs, and surrounding blood vessels. As they grow and multiply, they begin to block blood flow and cause inflammation, making it harder for your dog’s heart and lungs to function properly.
Common Signs of Heartworm Disease:
Persistent cough
Fatigue after mild activity
Decreased appetite
Weight loss
Difficulty breathing
Swollen belly (in advanced cases)
In severe cases, a blockage known as caval syndrome can occur, which is life-threatening and requires immediate emergency intervention.
How Do Vets Test for Heartworms?
Veterinarians use a simple blood test to detect heartworm proteins. If heartworms are detected, additional testing may be necessary to identify the severity of the infection. Annual testing is recommended, even if your dog is on preventative medication, to ensure early detection. If you miss a dose of monthly medication, give it late, or your dog spits or vomits it out, they are left unprotected.
The American Heartworm Society recommends that you have your pet tested for heartworm every 12 months and give your pet heartworm preventive medication 12 months a year.
Treatment for Heartworm in Dogs
Your veterinarian will inform you of the best treatment strategy for your dog based on the latest recommendations from the American Heartworm Society.
Treatment for heartworm disease is a carefully managed, multi-step process that targets both immature and adult worms while minimizing risk to the dog. At a high level, dogs are first stabilized and often given medications like antibiotics to weaken the worms and address associated bacteria. They then receive a series of injections to kill the adult heartworms living in the heart and lungs. As the worms die, they break apart and are gradually absorbed by the body, which can be dangerous, so strict rest and limited activity are essential during recovery. Dogs are placed on a heartworm preventive moving forward to avoid reinfection.
Most dogs can return to a normal, happy life after successful treatment, though some may have lasting damage to the heart or lungs, depending on the severity of the infection. Ongoing preventive care and regular vet checkups are essential to keep them healthy and heartworm-free.
Preventing Heartworm in Dogs
The good news? Heartworm disease is highly preventable with consistent care. Protection typically includes monthly heartworm preventatives—available in oral, topical, or injectable forms—along with annual testing and routine veterinary check-ups. Consult with your veterinarian on what treatment plan will work best for your dog. These preventative medications are highly effective because they eliminate immature larvae before they have the chance to develop into harmful adult worms.
Protecting Your Dog, Yard, and Family
Protecting your dog from heartworms goes beyond medication; it’s also about creating a healthier, less mosquito-friendly environment. Start by eliminating standing water around your yard, where mosquitoes breed, and try to limit your dog’s outdoor activity during peak mosquito hours, especially at dawn and dusk. For added protection, professional mosquito control services, like those offered by Mosquito Squad Plus, can help reduce mosquito and tick populations, making your outdoor spaces safer for both pets and family.
Creating a healthy outdoor space for your dog also means picking up the poop. Lingering dog waste can harbor harmful bacteria, parasites, and other disease-causing organisms, putting both pets and family at risk. Professional pet waste removal services from DoodyCalls are a simple, effective way to maintain a cleaner environment for your pup, giving you better peace of mind.
This Heartworm Awareness Month, make prevention a priority with proper medication, routine vet care, and a clean, well-maintained yard. Your dog’s heart will thank you.
Sources: American Heartworm Society, VCA Animal Hospitals, Pet MD