Parasitic
🔴 Fatal
Cryptobiosis (Cryptobia salmositica)
🦠 Cryptobia salmositica · Bodonidae (Kinetoplastida)
📋 Overview
C. salmositica multiplies in the blood plasma and causes a wasting disease characterised by severe normocytic normochromic anaemia. The parasite evades immune destruction by shedding a surface glycoprotein (a metalloprotease) that cleaves host antibodies. Leech control is the main management approach.
📊 Key Facts
Causative Agent
Cryptobia salmositica
Agent Family
Bodonidae (Kinetoplastida)
Onset to Peak
weeks–months
Geographic Range
Pacific Northwest North America — British Columbia, Washington, Oregon rivers
Transmission Routes
Transmitted by leech Piscicola salmositica; also water-borne
Primary Host
Pacific Salmon (Oncorhynchus spp.), Rainbow Trout
Vaccine
✗ None / Experimental
🩺 Clinical Signs
Severe anaemia (pale gills), exophthalmia, splenomegaly, ascites, reduced growth, lethargy, dark coloration.
🔬 Symptoms
🔬
Severe anaemia (pale gills)
Circulatory Subacute
🔬
Exophthalmia
Ophthalmic Subacute
🔬
Splenomegaly
Lymphatic Chronic
🔬
Ascites
Abdominal Chronic
🧪 Diagnosis
Blood smear (flagellates in plasma), PCR, haematological parameters (PCV <10%).
💊 Treatment
ℹ️ Treatment options are limited. Consult a qualified fish health professional.
Isometamidium (experimental), leech removal from water, reduce stress.
🛡️ Prevention
ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Control leech populations, screen incoming water, quarantine infected fish.