Oncorhynchus masou virus

Also known as: OMV

Oncorhynchus masou virus (OMV) is a viral disease of salmonids, particularly affecting coho and masu salmon, and rainbow trout. It is taxonomically classified within the Herpesviridae family. The virus is endemic to Japan but has also been reported in regions such as Kuwait. Clinical signs of infection include anorexia, darkened body coloration, skin ulcers, and lethargy—typical indicators of systemic disease. Mortality is especially high in juvenile fish, and survivors often develop external tumors, mainly on the head and jaw. OMV spreads via direct contact, excretions, and possibly through contaminated egg surfaces during spawning. While the virus has a significant impact on fish health, it poses no threat to human health.

Distribution: Japan and other reported locations
Hosts: Coho salmon, masu salmon, rainbow trout
Detection Methods: Cell culture – unspecified
Target Tissue: Skin