Shaina Montiel still remembers the ambulance ride.

At the age of 5, Montiel had felt sick for about a week, right around Halloween. She'd been vomiting frequently and had abdominal pain. At first, her doctor told her family it was just the flu. But as her symptoms worsened and the antibiotics she'd been prescribed didn't do much, it became clear something else was going on.

Montiel's parents eventually took her to a hospital where a different doctor figured out the truth: Montiel had hantavirus − and needed to get to a children's hospital for supportive care and close monitoring, immediately.

Montiel says her mother stills cries thinking about her harrowing experience with hantavirus, which, according to the Centers of Disease Control and Prevention, can have a fatality rate up to 38%, depending on the type of syndrome caused by it. At the time of her infection, Montiel says one of her doctors remarked that she was the youngest patient they'd seen yet survive the virus.

"My mom tells me that she remembers, when they did send me to the ambulance, that she was letting me know that, 'We're going to see you, but there's a possibility that you might wake up and be in heaven,' " Montiel says. "And I was like, 'OK, that's fine. I'm fine with that. I want to go to heaven.'"