Hm:

"long period of uncertainty began on 31 May 2010, when she stabbed her left thumb with a curved forceps while cleaning a cryostat—a machine that can cut tissues at very low temperatures—that she used to slice brain sections from transgenic mice infected with a sheep-adapted form of BSE. She pierced two layers of latex gloves and drew blood"

Later in the article:

""We conduct research only on mouse-adapted sheep prions, which have never been shown to be infectious to humans,” Aguzzi [neuropathologist at the University of Zurich] says."

It sounds like the assumption that mouse-adapted sheep prions can't infect humans may be flawed.