Isolation of Infectious Pancreatic Necrosis Virus from the Blood and Blood Components of Experimentally Infected Trout

Abstract

Experimental infection with infectious pancreatic necrosis virus (IPNV) was achieved in yearling rainbow trout (Salmo gairdneri) and 7-mo-old brook trout (Salvelinus fontinalis) by intraperitoneal inoculation and by water contact, respectively. Blood removed periodically from both groups of fish was fractionated and various blood components examined for virus. IPNV was recovered consistently from the plasma and mononuclear-enriched blood fractions of the rainbow trout from 1 to 19 d postinoculation (DPI) and also was detected in the mononuclear fraction on 33 DPI. In the brook trout virus was recovered from 3 to 40 DPI in the plasma and from 7 to 40 DPI in the mononuclear fraction. Thus a viremia appeared to be important in the early stages of experimental IPNV infection and infectious virus was found both free in the plasma and in association with an undetermined cell population present in the mononuclear component of blood.Key words: infectious pancreatic necrosis, blood, fish disease, Salmo gairdneri, Salvelinus fontinalis