B.C. provincial health officer Dr. Bonnie Henry says the teenager in Children’s Hospital with Canada’s first presumptive case of avian flu is in critical condition.

Henry said the teen was admitted late on Friday and their condition varied over the weekend but that as of Tuesday they had taken a turn for the worst.

It was first reported over the weekend that the teenager was at B.C. Children’s Hospital with a suspected case of H5 bird flu.

Health officials are assuring the public they are working to figure out how the patient acquired the infection and who else they might have contacted. Henry said they are confident at this point, given the contract tracing and the length of exposure that they have not identified anyone else who may be infected.

Henry said that the province has a robust system in place to test for suspected viruses.

“It’s called a presumptive positive because to be confirmed as a truly positive, even though we have confidence absolutely in the PCR tests that are done at the BC CDC lab, it needs to be confirmed at the National Microbiology Laboratory in Winnipeg,” Henry added.

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“Those samples are on their way to Winnipeg and we are likely to have that confirmation in the next hours or days.”

Click to play video: 'H5 avian influenza: B.C. reports 1st suspected human case of bird flu'

The teenager likely caught the virus from a bird or animal, the province said in a statement over the weekend.

Health officials are urging everyone to stay up to date with their vaccines and to practise good hygiene and wash their hands regularly.

Henry said the next step is to determine if anyone else is sick.

“The contact tracing over the past few days to make sure that there are not other cases out there that we’re missing to make sure that people who have been in contact with this young person during their infectious period are assessed, are tested and all of the people who have been in contact, either at home or in the hospital, are notified,” she added.

However, Henry said there is a possibility that health officials may not be able to determine a source of the infection.

“At this point, we have a number of leads that we’re following and we will be tracking down every one,” she added.

H5 bird flu is widespread in wild birds worldwide and is causing outbreaks in poultry and U.S. dairy cows, with several recent human cases in U.S. dairy and poultry workers.

Human-to-human transmission is rare and there has been no evidence of sustained transmission between humans, according to Health Canada.

It is an airborne virus and cannot be contracted from eating eggs or chicken.