Morphological Characteristics of Infectious Pancreatic Necrosis Yirus in Trout Pancreatic Tissue

Abstract

Electron microscopical observations were made of infectious pancreatic necrosis (IPN) virus in thin sections of pancreatic acinar cells of rainbow trout (Salmo gairdneri). The virus and trout used in this study were obtained from a naturally occurring IPN epizootic in Colorado trout hatcheries and rearing units in 1968. IPN virus particles were found in large numbers in pancreatic acinar cells. Virus particles were associated most often with inclusion bodies composed of masses of virus particles and cell debris or large crystalline aggregations that were encircled by a single-layered membrane. Mature virus particles were found to average 57 nm in diameter and were hexagonal in profile.