Unless the sequence in the report is incorrect, the 78 year old woman for whom she was caregiver would have have much more contact with whatever was behind this, yet she didn’t begin to hallucinate until after several others had already begun to do so. If she was aware that her caregiver’s hallucinatory condition seemed to be spreading to others, it could have been some sort of hysterical, psychosomatic reaction, I guess. Or, maybe she’d developed some sort of partial immunity due to frequent contact? No idea really, just speculating based upon what was reported.