28th ANNUAL EASTERN FISH HEALTH WORKSHOP April 21-25, 2003 Spring Viremia Of Carp Virus In The Upper Midwest Susan  Marcquenski1, Peter Dixon2, Rose-Marie Le Deuff2, Alyson Sheppard2, Becky Lasee3, and Joe Marcino4 1Wisconsin Department of Natural Resources,  Box 7921, Madison, WI 53707; 2 Centre for Environment, Fisheries, and Aquaculture Science, Weymouth, The Nothe, Weymouth, Dorset, UK DT4 8UB; 3 USFWS, La Crosse Fish Health Center, 555 Lester Avenue, Onalaska, WI 54650; 4Minnesota Department of Natural Resources, 500 Lafayette Road, St. Paul, MN 55155 Spring Viremia of Carp (SVC) virus (Asian genotype) caused a common carp (Cyprinus carpio) kill during May 2002, in Cedar Lake (WI). Cedar Lake discharges into the Apple River, which connects to the St. Croix River and ultimately the Mississippi River. We conducted follow up monitoring in Fall 2002 to determine whether the virus was contained in Cedar Lake.  Serum was collected in mid-September from common carp in Cedar Lake, the St. Croix River, and Park Lake (WI) and tested for SVCV antibodies using competitive immunoassay. In mid-October, water temperatures in Pool 10 of the Mississippi River were 7-9oC, so in addition to serum, kidney and spleen were collected for virology; kidney was cultured for bacteriology; and tissues from fish with clinical signs were fixed for histology.  Samples were collected by Department of Natural Resources personnel in Wisconsin (WI DNR), Iowa, Minnesota, and the U.S. Fish and Wildlife Service - La Crosse Fish Health Center.  Serum was processed by the Centre for Environment, Fisheries, and Aquaculture Science (CEFAS) in Weymouth, England.  Bacteriology, virology and histology samples were processed by the La Crosse Fish Health Center.  SVCV antibodies were present in Cedar Lake (54/54); the St. Croix River (34/40); and Pool 10 of the Mississippi River (128/164).  Antibodies were not detected (0/50) from Park Lake where there was no history of carp kills.  Although SVCV was not cultured from carp in Pool 10 of the Mississippi River, a numerous fish had mixed bacterial infections. Histology tissue blocks from historic carp kills in Wisconsin were sent to CEFAS and processed for SVCV using an in situ hybridization method and RT-PCR.  Tissues from a 1989 carp kill in the Petenwell Flowage (Wisconsin River) were considered positive for SVCV by both methods.  Genotyping of RT-PCR products indicated that the virus was the European genotype, not the Asian genotype. The carp sport fishery and wild baitfish harvest in Cedar Lake and connected waters were closed by WI DNR emergency rule (October/November 2002) to prevent inadvertent spread of the virus. Return to 28th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page