Evidence for intracellular absorption of virus by the Pacific oyster, crassostrea gigas

Abstract

The accumulation and release of virus by the Pacific oyster, Crassostrea gigas, was studied by autoradiographic methods. An insect picornavirus, cricket paralysis virus, was used as a model because of its taxonomic similarity to the human enteroviruses that might be encountered in effluent contaminated sea water. High concentrations of label accumulated in the mucus in the digestive tract when oysters were placed in sea water containing radioactively‐labelled virus. Lesser concentrations appeared in the epithelial cells of the digestive div‐erticula tubules and mid‐gut and in the connective tissues surrounding the digestive tract. Label was not apparent in the tissues of the gonads, gills, mantle, muscle, or labial palps. The amount of label in the mucus of the mid‐gut decreased during depuration. However, label persisted in the gut epithelium and connective tissue even after 64 h depuration. The distribution of radioactivity in the tissues was the same for both nucleic acid and protein coat‐labelled particles, suggesting that the virus maintained its integrity. These results provide further evidence that total removal of virus from shellfish by depuration is unsuccessful. © Crown 1986.