Heartworm Disease
What is it?
Heartworm disease is caused by a worm spread by mosquito bites. Larvae mature into foot-long worms that live in the heart and lung vessels, causing lasting damage. With mosquitoes active nearly year-round, Southwest Florida is a high-risk area.
What signs should I watch for?
Signs to watch for include mild, persistent cough; tiring easily with exercise; reduced appetite and weight loss; swollen belly from fluid in advanced cases; and sudden collapse (emergency).
How is it diagnosed and treated?
A blood test detects infection; X-rays, ultrasound, and other tests determine severity. Treatment is a staged protocol that kills adult worms over several months, with strict exercise restriction to lower the risk of complications.
Can it be prevented, and what's the outlook?
- Prevention is far safer and cheaper than treatment.
- Give heartworm prevention every month, all year, and test yearly.
- Indoor dogs are at risk too.
Reviewed by the Adler Veterinary Hospital veterinary team, October 2026.
Any dog, indoor dogs included; Southwest Florida is high-risk
Who's at risk:
Persistent cough, tiring with exercise, weight loss, swollen belly
Main signs:
Schedule a visit soon
Urgency:
When to call a vet right away
- Sudden collapse
- A cough that becomes severe
Not sure whether it can wait? Call us anyway. Our team can help you decide.
Source:
Related conditions
Collapsing Trachea
Mitral Valve Disease
Heart Disease (DCM)