Officials continue to investigate what caused the death of one child and sent 14 others to hospital with flu-like symptoms from a home on a First Nation in Alberta.

Emergency Medical Services have ruled out carbon monoxide poisoning or some other toxic substance, CTV Calgary’s Mark Villani reported on Thursday morning. He said they believe the cause of the illness is “medical in nature.”

Paramedics were called to the Stoney Nakoda First Nation, located approximately 60 kilometres west of Calgary, regarding two children in medical distress just before noon on Wednesday. When crews arrived, they discovered a four-month-old girl dead at the scene and another child in serious condition. Thirteen other patients, including four teenagers, were also transported to Alberta’s Children Hospital in Calgary.

As of Thursday afternoon, 10 patients remain in hospital. They include a two-year-old girl who is said to be in serious, but stable condition, the RCMP said. 

The affected individuals were all members of the same extended family and were inside the same home on the First Nation at the time of the emergency, Villani confirmed. Some had been sick for days.

The medical examiner has arrived in the community to investigate.

The Ministry of Indigenous Services has offered its support to the Stoney Nakoda First Nation during this difficult time.

While the exact source of the family’s illness has not yet been confirmed, the most recent flu season has been especially dangerous in Alberta. There have been 88 confirmed deaths in the province so far.

With files from CTV Calgary and CTV’s Alberta Bureau Chief Janet Dirks