If a animal is tested positive the human have to undergo about 2-4 vaccinations that might need to be repeated and will cost a great amount, or they die. The vaccination has a lot of side effects.
He had just taken in a raccoon so the squirrel could have gotten it from that, and they don't know if the owner had been lying about taking it outside.
This is all the owner's fault for not taking the squirrel to a proper animal sanctuary.
This study is 20 years old.