Susceptibility of Representative Great Lakes Fish Species to the North Carolina Strain of Spring Viremia of Carp Virus (SVCV).

Spring viremia of carp virus (SVCV) is a notifiable pathogen of the World Organization of Animal Health. Since SVCV was isolated in Lake Ontario in 2007, concern has grown about its spread in the Great Lakes basin and its potential negative impacts on fish species of importance in stock enhancement programs basinwide. The susceptibility of representative fish species from the families Cyprinidae (Fathead Minnow Pimephales promelas, Golden Shiner Notemigonus crysoleucas, Spotfin Shiner Cyprinella spiloptera, and Creek Chub Semotilus atromaculatus), Centrarchidae (Largemouth Bass Micropterus salmoides), Percidae (Walleye Sander vitreus), Salmonidae (Rainbow Trout Oncorhynchus mykiss), and Esocidae (Muskellunge Esox masquinongy) to SVCV was evaluated by experimental infection under laboratory conditions. Morbidity and mortality were recorded, and virus re-isolation, seminested reverse transcription PCR, and histopathological assessments were performed. Using intraperitoneal (i.p.) injection, Fathead Minnows and Golden Shiners were highly susceptible to SVCV (40-70% mortality). All dead or moribund and apparently healthy surviving Fathead Minnows and Golden Shiners were SVCV positive. The SVCV was also detected in challenged but healthy Spotfin Shiners (30%) and Creek Chub (5%). However, noncyprinid species exhibited no morbidity or mortality and were free of SVCV following an observation period of 30 d. In a follow-up experimental challenge, Fathead Minnows and Golden Shiners were SVCV challenged at 103 and 105 PFU/mL by means of waterborne immersion. After immersion, Fathead Minnows and Golden Shiners exhibited characteristic SVCV disease signs, but mortality was less (30% and 10% mortality, respectively) than that in fish with i.p. injections. The SVCV was detected in all mortalities and a subset of healthy Fathead Minnows and Golden Shiners. Necrotic changes were observed in the kidneys, liver, spleen, ovaries, and heart, and other histopathological lesions also occurred. These findings suggest that two of the four cyprinids tested are susceptible to SVCV-induced disease and that all four can act as potential carriers of SVCV in the Laurentian Great Lakes. Received January 11, 2017; accepted July 17, 2017.