RTFS/BCWD
Bacterial
🔴 Fatal
✓ Treatable
Flavobacterium psychrophilum Infection
🦠 Flavobacterium psychrophilum · Flavobacteriaceae
📋 Definition
Rainbow Trout Fry Syndrome (RTFS) and Bacterial Cold Water Disease (BCWD) in salmon — two manifestations of F. psychrophilum infection in salmonid fry at low temperatures.
📊 Key Facts
Causative Agent
Flavobacterium psychrophilum
Agent Family
Flavobacteriaceae
Geographic Range
Worldwide in cold-water salmonid aquaculture (<15°C)
Transmission Routes
Vertical (egg surface), water-borne
Primary Host
Rainbow Trout fry/fingerlings (RTFS), Coho Salmon (BCWD)
Vaccine
✗ None / Experimental
🩺 Clinical Signs
RTFS: mass mortality of fry with haemorrhagic lesions; BCWD: necrotic lesions at base of dorsal fin progressing to peduncle ulcers and spine exposure.
🔬 Symptoms
🔬
Peduncle ulcers
Integumentary Chronic
🔬
Mass fry mortality
Systemic Acute
🔬
Dorsal fin necrosis
Integumentary Subacute
🧪 Diagnosis
Culture on Shieh medium at 15°C, gliding motility, PCR.
💊 Treatment
Florfenicol, oxytetracycline.
🛡️ Prevention
ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Egg disinfection, reduce handling stress of fry.