The death of a child on the Stoney Nakoda First Nation on Wednesday is under investigation and health officials are working to determine the nature of the illness that killed the infant and sent 14 members of her immediate family to hospital with flu-like symptoms.

Emergency responders were called to the home on a rural property west of Calgary at about noon and found two children in medical distress.

A four-month-old girl was pronounced dead and a two-year-old girl was rushed to Alberta Children’s Hospital. Nine other children and four adults were taken to hospital for further assessment and treatment.

On Thursday afternoon, RCMP confirmed the 15 people in the home at the time of the emergency call were two parents and their 13 children, two of which are over the age of 18.

EMS officials say of the patients exhibited “influenza-like symptoms.”

"Most of the patients were stable enough, fortunately, to be able to go in more than one patient per ambulance. In the instance of the one child who was transported in serious condition, he was transported alone in the ambulance with a medical crew,” said Stuart Brideaux, EMS Public Education Officer.

Brideaux says the illnesses did not appear to be related to a noxious substance and that the cause appears to be ‘medically based’.

"At this time, EMS is working to sort out the potential origin of the circumstances," said Brideaux.

“We have brought in additional resources, some officers from the RCMP’s Major Crimes Unit are attending to help with the investigation and they will work along with the Cochrane RCMP and the medical examiner,” said Cpl. Peters. “We don’t know yet what it is we’re looking at. I heard some people ask earlier about a gas leak and we don’t believe that’s the case, that’s been ruled out.”

Two adult siblings of the little girl who died were released from hospital on Thursday and the rest of the patients are now in stable condition in hospital in Calgary.

Police say the death of the child is under investigation and that it will take some time for them to determine exactly what happened.

“It’s certainly very unusual. I don’t recall anything similar to this in my experience, where there’s been that number of people taken to hospital from a residence like that. It’s going to take a little while to piece it all together and find out what happened,” Peters said.

An autopsy has been scheduled for Friday, April 6.

The community is reeling from the infant’s death and is lending its support to the family.

“It’s a tragedy for sure and it’s affected every member of the community,” said Rob Lahache, CEO of Wesley First Nation. ‘We’ve received just an onslaught of support and the people have extended their well-wishes and their prayers and let us know that the community of Morley and Wesley First Nation in particular have been in their thoughts.”

The Ministry of Indigenous Services has reached out the Stoney Nakoda First Nation to offer support and is in the information-gathering stage.

The family's home on the Stoney Nakoda First Nation is situated approximately 55 kilometres west of Calgary city limits.