Reovirus-like infection of cultured summer flounder Paralichthys dentatus.

Examination via light and electron microscopy of juvenile summer flounder Paralichthys dentatus experiencing a subacute to chronic mortality revealed severe necrotizing hepatitis characterized by necrotic multinucleated giant cells (syncytia). The cytoplasms of syncytia contained paracrystalline arrays of reovirus-like particles, strongly suggesting that the epidemic was caused by the virus. This is the first report of a putative viral infection in summer flounder.