Of the 21,000 rainbow trout susceptible, the outbreak led to the death of 50 fish. Mortality and morbidity were only observed on fish which have reached commercial size.
The infected farm is located on the river Dretulja and is the only farm on that river.
The farm is existing from June 2013, and was populated only with fish originating from viral haemorrhagic septicaemia and infectious haematopoietic necrosis free farms.
In November and December, fish were moved in two shipments for restocking of open waters nearby Zapresic (Zagreb County).
