Screening for VHS in Minnesota waters

Viral hemorrhagic septicemia virus (VHSV) is a highly invasive and pathogenic virus of more than 30 fish species in the Great Lakes region. While the virus has yet to invade Minnesota, it has been detected in all Great Lakes and inland waters of Michigan, New York, and Wisconsin. Early detection of this devastating disease in Minnesota is critical for rapid intervention and management. VHS can cause high mortality rates in both farmed and wild fish populations, making it of great concern to aquaculturists and recreationalists alike.

This project used highly sensitive diagnostic tools to survey lakes and rivers in Minnesota for VHSV. The locations and species included in the survey were selected in partnership with the MN DNR based on introduction risk, susceptibility, popularity, and geographic distribution. Risk was determined through a variety of factors, such as connectivity to infected waters, conducive water temperatures, linear distance to infected waters, and nearby boater movement. From July 1, 2012 to June 30, 2014 a total of 4,552 fish from 36 bodies of water, eight of which were sampled each year, were negative for the virus. While Minnesota remains free of VHSV, the threats of introduction remain a concern for fish health managers. This study has informed future surveillance strategies, risk assessment, and improved confidence in current management approaches.