Parasitic
🔴 Fatal
Ceratomyxosis
🦠 Ceratomyxa shasta · Ceratomyxidae (Myxozoa)
📋 Overview
C. shasta destroys intestinal tissue causing fluid-filled swelling, peritonitis, and death. The polychaete worm Manayunkia speciosa serves as the alternate host. Hatchery fish from Columbia River populations vary widely in genetic resistance; some tributaries have extremely high parasite loads.
📊 Key Facts
Causative Agent
Ceratomyxa shasta
Agent Family
Ceratomyxidae (Myxozoa)
Onset to Peak
weeks–months
Geographic Range
Pacific Northwest North America (Columbia River basin)
Transmission Routes
Via aquatic oligochaete Manayunkia speciosa; water-borne spores
Primary Host
Salmon and trout (Oncorhynchus spp.), Pacific salmonids
Vaccine
✗ None / Experimental
🩺 Clinical Signs
Abdominal distension, yellow peritoneal fluid, liquefied gut contents, exophthalmia, lethargy, haemorrhagic intestines.
🔬 Symptoms
🔬
Abdominal distension
Abdominal Acute
🔬
Liquefied intestinal contents
Digestive Acute
🔬
Yellow peritoneal fluid
Abdominal Acute
🔬
Exophthalmia
Ophthalmic Subacute
🧪 Diagnosis
Histopathology of intestinal tissue, PCR for C. shasta, spore identification.
💊 Treatment
⚠️ No universally approved treatment is currently available. The information below covers supportive care and experimental approaches.
None effective. Fumagillin investigated but not licensed.
🛡️ Prevention
ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Use resistant hatchery strains, bypass high-parasite river sections.