Some aspects of virus shedding by rainbow trout (Salmo gairdneri Rich.) after waterborne infection with viral haemorrhagic septicaemia (VHS) virus.

VHS virus shedding after experimental waterborne infection of rainbow trout was quantified by measuring virus infectivity in blood, faeces, and urine of catheterised fish. Virus shedding by urine with relatively high yields of infectious virus could be demonstrated during acute VHS until death, but not by faeces. Trout, which were vaccinated against VHS or had survived the disease but showed no detectable humoral antibodies, may excrete infectious virus via urine for more than 30 days and without any signs of VHS after a secondary challenge infection. These results reveal the development of a carrier status of rainbow trout after VHS exposure.