A Fredericton family is keeping vigil at their daughter’s bedside as she battles a potentially deadly strain of E. coli.

Micaella Boer is one of four people in the Fredericton area who contracted the infectious bacteria, which is the same strain that killed seven people in Walkerton, Ont. in 2000.

The bacteria cause diarrhea, stomach cramps, and can lead to a fatal kidney disease.

The 18-year-old graduated from high school last month but instead of celebrating the happy occasion, she is now being treated at the Saint John Regional Hospital.

Her parents have been at her side for the last week.

“It’s concerning. As a parent you’re always worried for your child,” says parent Scott Boer. “Micaella probably on Monday, just after Canada Day, started getting stomach aches and complaining of cramps, some diarrhea, and by Tuesday it turned into bloody diarrhea and then later Tuesday night, we took her into emergency to get her checked out.”

They also say their daughter’s friend was admitted to the hospital just a day after she was. He too tested positive for E. coli, although it’s a slightly different strain.

“Everyone keeps asking me where she got it,” says her mother, Victoria Boer. “We just really have no idea. Between his mom and us, we’re trying to figure out where they were together.”

Medical health officials in the province are trying to figure that out too.

This is the second recent outbreak of E. coli in the region, after more than a dozen people were infected in Miramichi in the spring.

“They said that it was very quickly, this can become complicated with the type of immune system she’s got right now, if it’s left untreated, it’s a 100 per cent mortality rate,” says Victoria Boer.

Thankfully, the teen’s condition is improving and her parents say her young age has been a factor.

Health officials say three of the four people affected by the recent outbreak have been hospitalized and it could be awhile before they are able to track the source.

Micaella’s parents say she spent the last few weeks before she got sick attending graduation parties and events, and they are working with health officials to try to determine how she contracted the bacteria.

With files from CTV Atlantic's Ashley Dunbar