What happened to Chaya's parents?

Hannah Stern—whom everyone thinks is Chaya Abramowicz, has come down with an especially nasty bout of cholera, the illness that claimed the lives of her parents. While recuperating at the home of her Uncle Shmuel and Aunt Gitl, Hannah/Chaya starts talking about events from the future, which of course is where Hannah lives.
Not surprisingly, no one can make heads or tails of what she's saying. Everything that comes out of her mouth just sounds weird. Everyone also finds it rather odd that Chaya doesn't appear to recognize her own relatives. You'd think she'd never seen them before. (Which of course, she hasn't.) Both of these strange occurrences are attributed to Chaya's fever. The poor girl's so ill, it is believed, that she has no idea what she's saying.