Yes this is a big problem and completely not the animals fault but the unfortunate experiences they have had with humans as many have lost touch with nature completely, this is of course a shame as they lose out in potential for finally a good safe home but I'm surprised you don't get cases like this more often. There are indeed people out there that would take such tough cases and thanks to them some still have a chance, I hope in the end something good will happen for her.
RE: It can take months or longer to gain the trust of a rescue animal