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Parasitic ⚪ Sublethal

Henneguya Salminicola Infection

🦠 Henneguya salminicola · Myxosporea (Cnidaria-related)

📋 Overview

H. salminicola is notable for being an anaerobic metazoan — it lacks mitochondria and is the most complex animal known to not use aerobic respiration. The "milky flesh" condition in Pacific salmon is caused by plasmodia of this organism in muscle, and is a major quality issue in commercial harvest rather than a health crisis for fish.

📊 Key Facts

Causative Agent
Henneguya salminicola
Agent Family
Myxosporea (Cnidaria-related)
Peak Mortality
5%
Onset to Peak
months
Geographic Range
Pacific Northwest North America (Oncorhynchus rivers)
Transmission Routes
Via oligochaete intermediate host; spores in water
Primary Host
Pacific salmon (Chinook, Chum, Coho, Pink)
Treatment
✗ None
Vaccine
✗ None / Experimental
First Described
1893

🩺 Clinical Signs

White milky pockets or streaks in flesh (especially in chum and pink salmon), generally no external signs, fish remain active.

🔬 Symptoms

🔬
White milky pockets in muscle
Musculoskeletal Chronic

🧪 Diagnosis

Visual inspection of cut flesh; histopathology showing myxozoan plasmodia; spore morphology.

💊 Treatment

⚠️ No universally approved treatment is currently available. The information below covers supportive care and experimental approaches.
No treatment; affects market value only.

🛡️ Prevention

ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
No prevention; endemic in affected river systems.