Heartworm Disease: What Pet Owners Need to Know
Heartworm disease is a serious and potentially life-threatening condition that affects dogs, cats, and other animals. It is caused by parasitic worms that live in the heart, lungs, and blood vessels. With proper prevention and regular testing, heartworm disease is largely preventable.
What Is Heartworm Disease?
Heartworms are spread through the bite of an infected mosquito. When a mosquito bites a pet, microscopic heartworm larvae are transmitted into the bloodstream. Over time, these larvae mature into adult worms that can grow up to a foot long and live for years inside the heart and lungs.
Heartworm disease can cause lasting damage and, if left untreated, may be fatal.
Which Pets Are at Risk?
- Dogs are the most common host and can develop severe disease.
- Cats can also be infected, even if they live indoors. Heartworm disease in cats is harder to detect and has no approved treatment.
- Pets of all ages are at risk, even those that rarely go outside.
Because mosquitoes can enter homes, indoor pets are not fully protected by their lifestyle.
Signs of Heartworm Disease
Early infection often shows no symptoms. As the disease progresses, signs may include:
- Coughing or difficulty breathing
- Fatigue or reduced activity
- Weight loss or loss of appetite
- Exercise intolerance
- In severe cases, sudden collapse or heart failure
Cats may show vomiting, coughing, or sudden breathing distress.
Why Prevention Is Essential
Heartworm disease is far easier and safer to prevent than to treat. Treatment for dogs is expensive, lengthy, and can carry risks. There is no approved treatment for heartworm disease in cats, making prevention especially important.
Monthly preventatives work by killing immature heartworms before they develop into adults.
Heartworm Prevention Options
Veterinary-prescribed preventatives include:
- Monthly oral medications
- Monthly topical treatments
The right option depends on your pet’s species, age, weight, health status, and lifestyle.
Heartworm Testing
Dogs should be tested for heartworm disease regularly, usually once a year, even if they are on prevention. (In Ontario every 2 year is recommended, Unless the pet travels to a warm climate in the winter months).Testing ensures early detection and confirms that preventatives are working properly.
Cats may be tested based on risk factors and clinical signs.
Seasonal Protection Matters
Heartworm disease is present in many regions, including areas with colder winters. Because mosquitoes can survive indoors and during warmer periods, prevention is recommended from June-November. If traveling to warmer climates in the winter months year round prevention is recommended.
How We Can Help
Our veterinary team will:
- Recommend the safest and most effective heartworm prevention
- Perform routine heartworm testing
- Answer your questions about risks and protection
- Create a customized prevention plan for your pet
Contact us today or schedule an appointment to ensure your pet is protected from heartworm disease.