First isolation and identification of Sleeping Disease Virus (SDV) in Germany

Sleeping disease (SD) is widespread in Northern Europe. The SD virus (SDV affects fresh water reared rainbow trout (Oncorhynchus mykiss) and induces the typical listless or "sleepy" behaviour, where fish tend to aggregate at the lower parts of the pond. In Germany, SDV was isolated from diseased rainbow trout fingerlings in RTG-2 and CHSE-214 fish cell lines at 15 degrees C. Genome fragments of the German SDV isolates G1 and G2 and the reference viruses S49P (French SDV) and P42P (Scottish SPDV) were first identified by reverse transcription polymerase chain reaction (RT-PCR) as a 303 bp instead of a 284 bp fragment and also by indirect immunofluorescence assay (iIFA) after transfection of SDV RNA by electroporation to avoid contamination with Infectious Pancreas Necrosis Virus (IPNV) which is wide spread in German rainbow trout farms