Don’t ever try to clean up a rodent-infested or previously rodent-infested barn by sweeping. You will just get all the hanta virus into the air and breathe it in. Have it done professionally by people with face masks and vacuum cleaners.
Cleaned up a garage a couple of years ago. Deer mice infested with urine stains and feces everywhere including boxes and equipment. Got myself medically cleared, fit-tested with a full-face respirator with proper cartridge, Tyvek coveralls, booties, and gloves. Got after it with a spray bottle with 10% bleach followed by use of Craftsman wet-vac with HEPA filter. Took care of the problem myself and plastic bagged lots of destroyed papers and books and took to the waste transfer station. Knew I handled it safely with no adverse effects.
I spray down the rodent droppings with bleach. I figure that should take care of any hanta virus.