Do all bats have rabies?
No. Less than 1% of bats carry the rabies virus. In fact, “Fewer than 40 people in the United States are known to have contracted rabies from bats during the past 40 years” (U.S. Fish and Wildlife Service).
However, the bats that are infected are more likely to come into contact with humans. Bats in the late stages of the disease will be more likely to be found on the ground or flying erratically or enter rooms when the homeowner is sleeping. One key problem is when people, particularly children, try to "help" the downed bat and get bitten. Adults sometimes get bitten when endeavoring to remove a bat from the mouth of their pets and get bitten. Never attempt to handle bats without wearing thick leather gloves. Better yet, avoid doing it at all. Call a professional or get professional training.
In light of this experiential change, the likelihood of a bat being rabid that a person comes into contact with would be more like 2-3%.