Outbreaks of an EHNV‐like iridovirus in cultured rainbow trout, Salmo gairdneri Richardson, in Australia

Outbreaks of an EHNV‐like iridovirus in cultured rainbow trout, Salmo gairdneri Richardson, in... J. S. LANGDON, J. D. HUMPHREY & L. M. WILLIAMS Australian Fish Health Reference Laboratory, Benalla, Victoria, Australia The iridovirus responsible for epizootic haematopoietic necrosis (EHN) in redfin perch, Ferca fluviatilis L., was first isolated in 1984 in north-east Victoria, Australia, where EHN outbreaks are now known to be common during summer (Langdon, Humphrey, Williams, Hyatt & Westbury 1986a; Langdon & Humphrey 1987). The authors report here two outbreaks of a disease caused by a morphologically identical virus in cultured rainbow trout, Salmo gairdneri Richardson. Both cases were first noted in December 1986. The first case was in a group of 400 000 6-month-old fish introduced to the farm 3 weeks earlier. The second case was in 18-monthold fish purchased from the first farm 8 months earlier. Affected fish displayed darkening, ataxia and reduced feeding activity. Mortality was only slightly higher than normal at about 0-05% per day in the O-l- fish but the morbidity approached 100%. Fresh chilled O-l- fish received at this laboratory displayed slight abdominal distension and anal protrusion. Three- to 8-mm full-depth skin ulcers with a sharply defined border were seen on the lateral body surface of the 1+ fish and in follow-up samples http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Fish Diseases Wiley

Outbreaks of an EHNV‐like iridovirus in cultured rainbow trout, Salmo gairdneri Richardson, in Australia