A possibly new disease of Rainbow Trout has possibly been found in Sweden. Whilst the exact cause and significance of the disease which has occurred on two sites is yet to be determined it would appear to be associated with a protozoan parasite possibly of the Sarcocystidae family.
Mortality is variable but has been up to 15% in juvenile fish at approximately 1 month post hatching and of a length up to 2.5 cm. Clinical signs include increased mortality, a black discoloration to the posterior section of the body and swelling over the dorsal surface of the cranium.
Members should be aware of this condition and further details can be downloaded here.