Description

Bacterial kidney disease (BKD) was first reported in wild salmon populations of the Rivers Spey and Dee in 1933 and has since been reported in many other wild and farmed populations. It is a chronic infection that can occur throughout the year but often accompanies rising water temperatures in the spring. Nearly all age groups can be affected although it is rare in very young fish. The significant mortalities amongst infected fish occur over an extended period of time.

Signs of infection

These are variable. Some infected fish may show no visible signs of infection, whereas others may have all or a mix of protruding eyes, darkened skin, haemorrhage at the base of the fins and pale and anaemic gills. Internal signs include fluid accumulation in the body cavity and enlargement of the kidney.

Pathways

BKD can be transmitted through water but highest risk is through movement of live fish, discharge of untreated blood and contact with infected vehicles and equipment.