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Parasitic 🟡 Moderate

Kudoa thyrsites (Soft Flesh Syndrome)

🦠 Kudoa thyrsites · Kudoidae (Myxozoa)

📋 Definition

A myxozoan parasite that invades the muscle of marine fish, releasing enzymes post-mortem that cause "soft flesh" or "milky flesh" syndrome, rendering the product unsaleable.

📊 Key Facts

Causative Agent
Kudoa thyrsites
Agent Family
Kudoidae (Myxozoa)
Peak Mortality
5%
Onset to Peak
months (post-mortem expression)
Geographic Range
Worldwide in marine fish (Atlantic salmon farming)
Transmission Routes
Unknown (complex myxozoan life cycle)
Primary Host
Atlantic Salmon, Pacific Salmon, Many wild marine fish
Treatment
✗ None
Vaccine
✗ None / Experimental
First Described
1917
Economic Impact
Significant: affects product quality — liquid flesh unsaleable

🩺 Clinical Signs

No clinical signs during life. After slaughter, infected muscle liquefies within hours, producing a milky, watery texture unacceptable to market.

🔬 Symptoms

🔬
Post-mortem muscle liquefaction
Musculoskeletal Post-mortem
🔬
Milky muscle texture
Musculoskeletal Post-mortem

🧪 Diagnosis

Histopathology (pseudocysts in muscle), PCR, post-mortem muscle consistency test.

💊 Treatment

⚠️ No universally approved treatment is currently available. The information below covers supportive care and experimental approaches.
No treatment. Strategic harvesting during low-infection periods.

🛡️ Prevention

ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Site selection, monitoring of wild carrier fish in area.