A fatal fish virus has been detected in Lake Superior for the first time, meaning it has spread to all the Great Lakes, Cornell University researchers said Wednesday.

Scientists said they recently detected the viral hemorrhagic septicemia, or VHS, while testing fish in the largest of the Great Lakes.

VHS has been identified in 28 freshwater fish species within the Great Lakes watershed since 2005, including sport and commercial varieties such as walleye, muskellunge and whitefish. It causes bleeding, bloated abdomens and bulging eyes in fish before killing them.

Although not dangerous for humans, the virus has caused large fish kills in Lakes Ontario, Erie and Huron. It also has turned up in Lake Michigan.

Even so, officials in Michigan and Wisconsin said Wednesday there was no evidence of a widespread outbreak in Lake Superior. They said the Cornell findings would not lead to any immediate changes in boating or fishing regulations.

Both states already limit movement of bait fish and have other rules aimed at preventing VHS from spreading.

"VHS remains a threat to all the Great Lakes, and we will increase our efforts to slow the spread through public awareness of the simple things boaters and anglers can do to help," said Rebecca Humphries, director of the Michigan Department of Natural Resources and Environment.

State officials said it was understandable that VHS would have worked its way into Lake Superior, which is connected to Lake Huron by the St. Marys River.

"We're disappointed with Cornell's finding but not surprised," said Matt Frank, director of the Wisconsin Department of Natural Resources.