Vet Guide 2025: Pseudocapillariasis in Reptiles & Amphibians 🦎🐸🐢 by Dr Duncan Houston 🩺

Hello! I’m Dr Duncan Houston, BVSc and founder of Ask A Vet. Pseudocapillariasis is an uncommon but significant parasitic disease of reptiles and amphibians caused by capillariid nematodes (historically "Capillaria"). In this comprehensive 2025 guide, I’ll explain the parasites’ lifecycle, clinical signs—whether intestinal, cutaneous or hepatic—how we diagnose and treat them, and what husbandry measures help prevent infection.

1. What Are Capillariid Nematodes?

Capillariid worms (Genus *Capillaria*, now including *Pseudocapillaria*, *Paracapillaria*, etc.) are thread-like parasites that infect the intestines of reptiles and amphibians, occasionally migrating to liver, bladder, or skin in amphibians such as frogs ([turn0search1], [turn0search8]). While *Entamoeba* protozoa are more common in reptiles, capillariids remain the only trichurid nematode infecting them ([turn0search1]).

2. How Infection Occurs

• Occurs via ingestion of embryonated eggs or through infected intermediate hosts (earthworms, crustaceans).
• Eggs are passed in feces and require time to become infective in substrate or invertebrates ([turn0search1]).
• Lack of substrate hygiene or mixed-species housing increases risk.

3. Species Affected & Parasite Behavior

• Reptiles: snakes, lizards, turtles mainly with intestinal infection.
• Amphibians: frogs (e.g., *Xenopus laevis*) may also develop cutaneous or hepatic capillariasis (*Pseudocapillaria/Pseudocapillaroides*), causing wasting and skin lesions ([turn0search7]).
• Some infections are incidental, but heavy burdens lead to disease manifestations.

4. Clinical Signs & Health Impact

• Gastrointestinal disease: anorexia, weight loss, vomiting/regurgitation, diarrhea, lethargy, anemia, intestinal obstruction, peritonitis in severe cases ([turn0search1], [turn0search8]).
• Cutaneous form: granulomas, scarring, skin erosions, particularly in frogs with external egg or parasite stages ([turn0search7]).
• Hepatic cases: liver enlargement, failure to thrive, especially in amphibians where parasites embed in hepatic tissue.

5. Diagnosis

• Fecal flotation/microscopy: detection of operculated eggs typical of capillariids ([turn0search1], [turn0search8]).
• Wet mounts: visualization of eggs or worms under microscope aids identification.
• Skin/lesion biopsies: indicated for cutaneous infections in amphibians ([turn0search7]).
• Imaging/endoscopy: may detect intestinal thickening or masses in severe cases.

6. Treatment Strategies

6.1 Anthelmintics

• **Fenbendazole** (50–100 mg/kg PO, repeat after 2 weeks) effectively treats intestinal parasite forms ([turn0search1], [turn0search8]).
• **Levamisole** or **ivermectin** have also been used; caution indicated in chelonians/skinks ([turn0search1], [turn0search7]).
• For cutaneous cases in frogs, **levamisole via tank water** was effective ([turn0search7]).

6.2 Supportive & Symptomatic Care

• Restore hydration, correct anemia, adjust nutrition.
• Treat secondary issues like GI distress or skin ulcers.
• Warm environment (80–90 °F) supports immune response.

7. Prognosis

Most intestinal cases respond well to thorough deworming and husbandry improvements, though heavy burdens or complications (obstruction, liver involvement) carry higher risks. Cutaneous or hepatic cases require close monitoring—some populations may relapse without repeated deworming.

8. Environmental Management & Prevention

• Quarantine new animals 60–90 days with serial fecal exams.
• Maintain substrate hygiene: clean feces promptly, disinfect surfaces regularly.
• Remove unknown invertebrates—worms, snails, insects—from enclosures.
• Avoid mixed-species housing that may harbor intermediate hosts.
• Adopt strict biosecurity when managing amphibian populations—separate tanks, tools.

9. When to Use Ask A Vet 🩺

Noticed GI signs, skin lesions, or weight loss in your reptile or amphibian? Upload fecal images, enclosure photos, and clinical info via the Ask A Vet app for tailored guidance—dosing, diagnostics, environmental cleanup steps. Available anytime at AskAVet.com 📱

10. Final Thoughts

Pseudocapillariasis, while less common, can significantly harm reptile and amphibian health. Through fecal testing, effective anthelmintic therapy, supportive care, and diligent husbandry, most pets fully recover. In amphibians with cutaneous or hepatic forms, complete eradication may require repeated treatment and tank decontamination. With Ask A Vet’s support, you can catch this disease early and help your reptile or amphibian thrive into 2025 and beyond. 🩺🌿

— Dr Duncan Houston, BVSc