Overview
Heartworm disease is caused by parasitic worms that live in the heart and pulmonary arteries, transmitted by mosquito bites. In dogs, worms grow up to 12 inches and can cause heart failure and death. In cats, even 1-2 worms can be fatal — and there is no approved treatment for cats, only prevention. It takes 6-7 months after a mosquito bite for worms to mature, so early detection requires regular testing.
Symptoms to Watch For
- Mild persistent cough
- Exercise intolerance and fatigue
- Decreased appetite and weight loss
- Swollen abdomen (from heart failure)
- Sudden collapse or death in severe cases
How Nutrition Helps
Nutrition doesn’t prevent or treat heartworm, but supporting heart health with omega-3 fatty acids and taurine helps the heart cope with the burden of infection. During treatment in dogs (which kills worms, creating dangerous inflammation), anti-inflammatory nutrition supports recovery. A strong immune system may reduce infection severity.
How Activity Helps
During heartworm treatment, strict exercise restriction is mandatory — physical activity can cause dead worm fragments to block pulmonary arteries, potentially killing the dog. Post-treatment, gradual return to activity over 6-8 weeks.
Prevention Tips
- Year-round heartworm prevention medication — no exceptions
- Annual heartworm testing for dogs
- Monthly preventives work retroactively — a missed month is dangerous
- Minimize mosquito exposure
- Prevention is far safer and cheaper than treatment