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Fungal 🟡 Moderate

Ichthyophonus Infection

🦠 Ichthyophonus hoferi · Ichthyophonidae

📋 Definition

A systemic infection caused by the mesomycetozoean Ichthyophonus, forming granulomatous cysts throughout internal organs, commonly causing "sandpaper liver."

📊 Key Facts

Causative Agent
Ichthyophonus hoferi
Agent Family
Ichthyophonidae
Peak Mortality
40%
Onset to Peak
months
Geographic Range
Worldwide — marine and freshwater fish
Transmission Routes
Ingestion of infected fish or tissue
Primary Host
Atlantic herring, Atlantic mackerel, rainbow trout, plaice
Treatment
✗ None
Vaccine
✗ None / Experimental
First Described
1893

🩺 Clinical Signs

Rough sandpaper texture of internal organs (especially liver and heart), yellow/white granulomatous cysts throughout viscera, heart failure, external skin ulcers, lethargy.

🔬 Symptoms

🔬
Granulomatous cysts in internal organs
Systemic Chronic
🔬
Sandpaper liver texture
Hepatic Chronic
🔬
Heart failure
Circulatory Chronic

🧪 Diagnosis

Post-mortem: characteristic granulomas visible grossly, large spherical thick-walled resting stages on histopathology.

💊 Treatment

⚠️ No universally approved treatment is currently available. The information below covers supportive care and experimental approaches.
No effective treatment.

🛡️ Prevention

ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Feed fish with cooked/processed feed rather than raw fish.