Vet’s 2025 Guide to Lungworms in Dogs 🩺🐶

By Dr. Duncan Houston BVSc

Lungworms are parasitic worms that infect the lungs and airways of dogs, potentially causing coughing, breathing problems, and in severe cases, lung damage or pneumothorax. Early recognition, proper diagnosis, and treatment are essential. In this 2025 guide, Dr Houston outlines everything you need to know: causes, symptoms, diagnostic steps, treatments, prevention, and supportive care.

1️⃣ What Are Lungworms?

Lungworms include several species of nematodes and flukes that affect dogs. In North America, common species include Eucoleus aerophilus, Oslerus osleri, Crenostoma vulpis, and Filaroides hirthi, as well as heartworm-related Angiostrongylus vasorum in Europe and the UK.

The life cycle involves ingestion of larvae through snails, slugs, or infected intermediate hosts (like crayfish) and migration to the lungs via blood or lymphatic routes.

2️⃣ How Dogs Get Lungworms

Dogs become infected by:

• Eating snails or slugs carrying infective larvae (e.g., C. vulpis).
• Swallowing slime trails on toys, grass, or water bowls contaminated with larvae.
• Ingesting other animals (frogs, rodents) that carry larvae.
• Transmission via saliva or grooming (especially in Oslerus osleri).

3️⃣ Who Is at Risk?

• All dogs, at higher risk in curious young pups.
• Dogs in areas with high slug/snail populations (e.g., moist, shaded kennels).
• Dogs that consume prey animals (e.g., frogs, crayfish).
• Dogs in Europe and UK may be exposed to A. vasorum.

4️⃣ Recognising the Signs

Symptoms vary from mild to severe depending on worm burden and species:

• Non‑productive cough, exercise intolerance, increased respiratory rate.
• Difficulty breathing, wheezing, lung inflammation or pneumonia.
• Weight loss, lethargy, decreased appetite, occasional vomiting, or diarrhea.
• Bleeding disorders (especially with A. vasorum)—including prolonged bleeding or clotting issues.
• Pneumothorax from cyst rupture—coughing or sudden breathing distress.

5️⃣ Diagnosing Lungworms

• Chest X‑rays: Show lung spots, pneumonia, nodules, or air pockets.
• Fecal tests: Baermann technique for larvae; flotation for eggs.
• Airway wash (TTW/BAL): Samples the fluid to identify larvae, eggs, or inflammatory cells.
• Bronchoscopy: Detects nodules and collects biopsy.
• Bloodwork: May show eosinophilia or inflammation.

6️⃣ Treating Lungworms 🩺

Treatment involves eliminating the parasite and reducing inflammation:

• Dewormers: Fenbendazole (50 mg/kg) for 7–14 days; ivermectin; milbemycin; imidacloprid/moxidectin; milbemycin + praziquantel.
• Corticosteroids: Prednisolone to reduce inflammation, especially in heavy infections.
• Supportive care: Oxygen, chest tube for pneumothorax, bronchodilators, fluids, and appetite support.
• Hospitalisation: Recommended for severe cases with respiratory distress or pneumothorax.
• Follow-up diagnostics: Repeat fecal and imaging tests after 2–4 weeks to confirm clearance.

7️⃣ Prognosis & Outlook

• Generally good: Most dogs recover with prompt treatment.
• Pneumothorax or heavy burden: More serious; may require chest drainage/surgery.
• Inflammatory sequelae: Airway scarring may cause a chronic cough, needing long-term management.
• Bleeding complications: From A. vasorum may be fatal if untreated.

8️⃣ Preventing Lungworm

• Monthly heartworm/lungworm preventatives in endemic areas.
• Clean outdoor water bowls and toys daily; store indoors overnight.
• Avoid snail/slug ingestion—clear garden areas where possible.
• Regular vet fecal exams and follow local parasite alerts.

9️⃣ Supportive Care & Brand Integration

• Use Ask A Vet for telehealth check-ins during treatment—monitor breathing, appetite, meds.

🔟 When to Contact Your Vet Immediately

• Persistent or worsening cough, rapid or labored breathing
• Signs of pneumothorax—sudden respiratory distress, collapsed posture
• Bleeding, bruising, seizures (suggestive of A. vasorum)
• Poor appetite, weight loss, lethargy
• Positive lungworm in fecal sample—begin treatment promptly

🏁 Final Thoughts

Lungworm infections in dogs are serious but usually manageable. With early detection, proper diagnostics, medications, and follow-up care—combined with prevention strategies and supportive TLC—dogs can make a strong recovery in 2025. Keep your vet, or telehealth via Ask A Vet, in the loop, and use calming and enrichment tools to support your pup's journey. 🐶💕

For expert guidance, follow-up care, or urgent advice, visit AskAVet.com and download the Ask A Vet app—support is available 24/7. 📱