TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 Diagnosis Of Two Emerging Virus Infections In The Bay Of Fundy D.A. Bouchard1, H.M. Opitz2, B.L. Nicholson2, S. Blake2, and W.R. Keleher1 1MicroTechnologies, Inc. Richmond, ME; 2University of Maine, Department of Microbiology, Orono, ME Hemorrhagic kidney syndrome (HKS) is a disease that was first described in July 1996 among pre-market Atlantic salmon in the Bay of Fundy. Histological analysis was the primary diagnostic indicator of HKS prior to the isolation of the etiological agent. Infected fish had extensive hemorrhaging in the posterior kidney and degenerative changes in the excretory renal tissue. Research and Productivity Council (RPC; Fredericton, NB) was the first laboratory to confirm the presence of Infectious Salmon Anemia Virus (ISAV) in August 1997 from HKS positive fish. To date, the disease presently referred to as HKS/ISA has been confined to three bays within New Brunswick (Canada) affecting 21 fish farms. In August 1997, during the outbreak of HKS at an Atlantic salmon grow-out site in Bliss Harbor (NB) samples were collected by MicroTechnologies, Inc. to isolate the causative agent. Duplicate samples of spleen and posterior kidney were collected from each of 20 fish for histological and virological analysis. Sixteen of 20 histology samples exhibited pathological signs indicative of HKS. Samples processed for virus isolation were all found to produce a cytopathic effect (cpe) on CHSE-214 cells at 14-28 days. Cellular material from these wells was found to possess virions 80-90 nm in size which were very pleomorphic. From the supernatants of these same wells, virus was confirmed by RT-PCR as ISAV by the University of Maine, Department of Microbiology with a sequence homology of 90% to a previously described Norwegian isolate. During the course of identification of the HKS agent, a separate virus was isolated by the Atlantic Veterinary College (Charlottetown, PEI). This virus was tentatively identified as a member of the Togaviridae family. Present data suggests that this virus is not associated with HKS. During the course of routine broodstock testing in the winter of 1997-1998, over 3500 were examined from 10 farms in the Maine and New Brunswick areas of the Bay of Fundy. Isolation of the virus occurred on the CHSE-214 cell lines at >9 days post inoculation with most observed cpe occurring near day 21. This "togavirus" was found in 27% of the pooled fish tested with all farms except one having the virus present. Currently, electron microscopy and molecular characterization work is being conducted at the University of Maine. Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page