National Heartworm Awareness Month 2026: When It Is & Health Tips

More than 1 million pets throughout the United States have developed heartworm and are suffering from the consequences1. Heartworm is a preventable disease with the help of effective medication that can be found over the counter and through veterinarians. However, people cannot protect their pets from heartworm if they don’t know about the dangers and how to implement safety measures.

Therefore, April has been designated as National Heartworm Awareness Month. The idea is to make as many pet owners aware of the dangers of heartworm as possible and provide them with information about how to prevent their pets from getting infected with the disease. Here’s what you should know about heartworm and why it’s so important to raise awareness in your community.

The History of National Heartworm Awareness Month

Heartworm infections in dogs were discovered way back in 1856, but it wasn't until 1992 that infestations were discovered in cats2. In 1972, the American Heartworm Society was born to help bring awareness to the disease. By 2020, the disease had become so prevalent that industry leaders felt that it was necessary to establish a national awareness month.

Here's How Pets Become Infected With Heartworm

Heartworm is a disease that is transmitted to pet dogs and cats by mosquitoes via biting. After the bite, larvae start to circulate throughout the blood of the pet that has been infected. The larvae develop into small spaghetti-like worms as time goes on, and these worms begin to infiltrate the heart and lung blood vessels.

Heartworms can grow to a staggering 12 inches in length when fully grown, so each one puts a great deal of stress on an animal’s internal system. These worms can live up to 7 years before they die off and get absorbed by the body. Pets can be infected with hundreds of heartworms at one time, and infection can go on for weeks, if not months, before signs become apparent.

Here Are the Signs of Heartworm Disease

No signs typically develop during the early stages of heartworm disease. However, as the disease develops, certain signs may start to become noticeable to pet owners. Highly active dogs, those with health preconditions, and those with heavy infections tend to show signs the most predominantly.

Here are the signs of heartworm that pet owners should always be on the lookout for:

• Persistent cough
• Fatigue
• Decreased appetite
• Weight loss
• Reluctance to exercise

Once the disease progresses to a serious level, a swollen belly and heart failure may develop quickly. Therefore, if any signs of heartworm disease are displayed, pet owners need to schedule a checkup appointment with their veterinarian as soon as possible.

Here’s How to Prevent Heartworm Disease

The most effective way to prevent the development of heartworm disease in pets is to administer preventative heartworm medication to them on a regular schedule throughout the year. These medications come in oral, injectable, and topical formulas, depending on things like your pet’s temperament and tolerance. While oral and topical medications must be administered monthly, injectable medications can be administered once every 6 months.

If you have any concerns about your dog or their health, we recommend you contact your vet directly.

Conclusion

National Heartworm Awareness Month is an important event. The more pet owners who are aware of heartworm disease and how to prevent it, the more pet lives we can save as time goes on. However, April is not the only good time to remind your friends and family about the importance of heartworm prevention. Reminders are encouraged all year long!

Featured Image Credit: hedgehog94, Shutterstock