CHIPPEWA FALLS, Wis. (WEAU)-- The Chippewa Falls Mayor says two more bison have died at the Irvine Park Zoo.
Mayor Greg Hoffman says the two died within the last week.
Four bison total have now died at the zoo. There are five bison left.
A veterinarian said earlier the bison came down with a disease spread by sheep.
The bison shared a fence with the sheep and it's believed that's most likely how the virus spread.
The sheep have since been moved.