Epizootic Hematopoietic Necrosis Virus

Also known as: EHNV

Epizootic Hematopoietic Necrosis Virus (EHNV) is a serious viral disease primarily affecting finfish, especially redfin perch (Perca fluviatilis) and rainbow trout (Oncorhynchus mykiss). It is caused by a ranavirus within the family Iridoviridae. EHNV causes systemic infections that result in high mortality, particularly in juvenile fish. Clinical signs include lethargy, abnormal swimming, darkening of the skin, and hemorrhages. Internally, affected fish may show swollen kidneys and spleens, with extensive necrosis of hematopoietic tissues. The virus is environmentally resilient and can persist in water and sediment, posing a risk of spread through contaminated equipment and live fish movement.

Distribution: Reported in Australia; potential risk to susceptible species globally
Detection Methods: Virus isolation; PCR; histopathology
Hosts: Redfin perch (Perca fluviatilis), rainbow trout (Oncorhynchus mykiss), and other susceptible freshwater fish
Target Tissue: Hematopoietic tissue, spleen, kidney, liver