If you buy minnows for bait, the Michigan Department of Natural Resources says you should try to make sure they are certified as free of viral hemorrhagic septicemia, or VHS. Certified disease-free bait is widely available and can be used anywhere for two weeks after purchase.
Bait that isn't certified can be used anywhere in the state if it comes from areas designated as free of VHS. But bait that isn't certified and comes from places with other VHS designations can be used only in certain areas.
For information on the status of a particular waterway, go to http://www.michigan.gov/vhs .