Publication Abstract

Pathology and ultrastructure of a non-occluded, intranuclear bacilliform virus (IBV) infecting brown shrimp Crangon crangon (Decapoda: Crangonidae)

Pathology and ultrastructure of a non-occluded, intranuclear bacilliform virus (IBV) infecting brown shrimp Crangon crangon (Decapoda: Crangonidae)

G.D.Stentiford, K. Bateman and S.W. Feist

The brown shrimp (Crangon crangon) supports a very important fishery in Europe (over 25,000 t, value 80 M ECU in 2000). Through the course of histopathological screening of crustaceans from the Clyde estuary, western Scotland, for the biological effect of contaminants, we have discovered a highly prevalent (up to 100 %) non-occluded intranuclear bacilliform virus (IBV) infection in the hepatopancreatic tubule epithelia and midgut epithelia of wild C. crangon. This is the first report of an IBV in this family. We have termed this virus Crangon crangon bacilliform virus (CcBV). Ultrastructural and pathological observations suggest that this virus is similar to other IBVs (or non-occluded baculoviruses) previously described from crabs and penaeid shrimps. Virus-infected epithelial cells contained eosinophilic, hypertrophied nuclei with marginal chromatin. The basement membrane of infected cells was often separated from that of its neighboring cells and their nuclei appeared apoptotic. In heavily infected shrimp, apoptotic cells were expelled into the lumen of the hepatopancreatic tubule or the midgut. Following this stage, some hepatopancreatic tubules became degenerate, with remnants of the basement membrane and myoepithelial lining remaining. Transmission electron micoscopy of hypertrophic nuclei revealed the presence of rod-shaped and cylindrical, envelope-bound virions. These virions did not forming arrays and were not encapsulated within occlusion bodies but did appear to be partially occluded in an amorphous matrix which corresponded to a granular viroplasm. The ultrastructure, morphology and size of the nucleocapsid and of the complete virion associated them most closely with the intranuclear bacilliform viruses (IBVs) previously reported from other decapod crustaceans. Due to the pathological manifestation of IBV infection in C.crangon, it seems likely that it can act as a population modulator, particularly at sites where infection prevalence is high, such as that observed in the Clyde estuary.

Reference:

G.D.Stentiford, K. Bateman and S.W. Feist (2004) Pathology and ultrastructure of a non-occluded, intranuclear bacilliform virus (IBV) infecting brown shrimp Crangon crangon (Decapoda: Crangonidae). Diseases of Aquatic Organisms, 58(2/3): 89-97

G.D.Stentiford*, K. Bateman* and S.W. Feist*

Diseases of Aquatic Organisms, 58(2/3): 89-97