Capillaria Infection in Cats: A Vet’s 2025 Guide to Bladder & Lung Worms 🐾🩺

Capillaria Infection in Cats: A Vet’s 2025 Guide to Bladder & Lung Worms 🐾🩺

By Dr Duncan Houston, BVSc

🔍 What Are Capillaria Worms?

Capillaria are slender parasitic nematodes that can infect cats—commonly in the urinary bladder (Capillaria plica/feliscati) and, less often, in lungs or nasal passages (Capillaria aerophila) :contentReference[oaicite:3]{index=3}.

🐾 Where They Live & Who They Affect

• Bladder worms (C. plica/feliscati) attach to bladder or ureter walls :contentReference[oaicite:4]{index=4}.
• Lung worms (C. aerophila) inhabit airways, rare in cats but more common in foxes/dogs :contentReference[oaicite:5]{index=5}.
• All ages can be infected, but bladder cases often seen in cats >8 months old :contentReference[oaicite:6]{index=6}.

⚠️ Symptoms to Watch For

Urinary Signs (Bladder Worms)

• Frequent urination or straining to urinate
• Blood in urine, painful urination
• Accidents outside litter box :contentReference[oaicite:7]{index=7}
• Possible urinary obstruction in heavy infections :contentReference[oaicite:8]{index=8}

Respiratory Signs (Lung Worms)

• Coughing, sneezing, wheezing, difficulty breathing :contentReference[oaicite:9]{index=9}
• Poor appetite, lethargy, fever :contentReference[oaicite:10]{index=10}

Other Variants

• Capillaria boehmi (nasal worm): sneezing, nasal discharge :contentReference[oaicite:11]{index=11}
• Gastrointestinal forms (e.g., C. putorii): vomiting or diarrhea—rare :contentReference[oaicite:12]{index=12}

🔬 How Cats Get Infected

All species share a similar lifecycle:

1. Eggs from urine or feces embryonate in environment.
2. Earthworms eat eggs—larvae develop inside.
3. Cat ingests earthworm, transport host, or contaminated material :contentReference[oaicite:13]{index=13}.
4. Larvae migrate → bladder (urinary species) or lungs (respiratory) and mature.

🩺 Diagnosis

• Urinalysis: bladder worms are diagnosed by detecting characteristic eggs in urine sediment :contentReference[oaicite:14]{index=14}.
• Fecal exam or airway lavage: respiratory species diagnosed via feces or nasal/tracheal samples :contentReference[oaicite:15]{index=15}.
• Repeat testing may be needed—eggs often shed intermittently :contentReference[oaicite:16]{index=16}.
• Imaging: used if complications like bladder thickening or lung inflammation are suspected.
• Bloodwork: help evaluate overall health and support diagnostics.

💊 Treatment Options

• Fenbendazole: off-label, commonly prescribed; effective for most Capillaria worms :contentReference[oaicite:17]{index=17}.
• Ivermectin or levamisole: alternatives when appropriate :contentReference[oaicite:18]{index=18}.
• Anti-inflammatories: prednisolone for symptomatic bladder inflammation :contentReference[oaicite:19]{index=19}.
• Supportive care: fluids, pain relief, rest if respiratory distress or obstruction occurs.
• Monitor: follow-up urine/fecal testing ensures complete clearance.

📅 Prognosis & Follow-Up

• Generally good: most cats recover fully after deworming :contentReference[oaicite:20]{index=20}.
• Severe bladder infections: may cause temporary urinary obstruction or cystitis :contentReference[oaicite:21]{index=21}.
• Respiratory cases: usually mild; heavy infections may lead to bronchitis or pneumonia :contentReference[oaicite:22]{index=22}.
• Retesting: recommended a few weeks post-treatment to confirm eradication.

🛡️ Prevention Tips

• Keep cats indoors to reduce exposure to earthworms or rodents :contentReference[oaicite:23]{index=23}.
• Avoid feeding raw prey or allowing outdoor hunting.
• Maintain clean litter boxes and environments.
• Regular deworming helps prevent uptake of parasites :contentReference[oaicite:24]{index=24}.
• Yearly wellness exams include urine/fecal screening—early detection is key.

🐾 Tips for Cat Parents

• Record changes in urination frequency, behavior or respiratory symptoms.
• Ensure full medication course; never skip doses.
• Follow your vet’s instructions on follow-up testing.
• Provide supportive care—ease stress and comfort your cat during recovery.
• Stay in touch via Ask A Vet for advice between visits; use calming Woopf & Purrz products.

📝 Consolidated Summary

🐾 Help your cat stay worm‑free with expert advice from Ask A Vet—download the app for peace of mind. Ease recovery with soothing products from Woopf and Purrz.

📢 Always follow your veterinarian’s diagnosis and treatment plan.

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