How could someone have contracted rabies in the u.S.?

Mostly via bat bite. Rabies virus is present in the saliva of rabid animals (bat, raccoon, skunk, fox, and coyote) and is transmitted by bites.
Rabies in the U.S.A. Rabies is extremely rare in the United States -- that's because in the 1940s we realized we needed to vaccinate all our dogs. Cases dropped from around 100 a year to 2 or 3. Usually these cases are from bat/wildlife exposures, or are 'imported' cases - where people are bitten by a rabid animal in another country, then come to the U.S. Rabies can 'hide' for months or even years in some cases.