A London, Ont.-area youth has been diagnosed with severe respiratory illness linked to vaping products, the Middlesex-London Health Unit (MLHU) said Wednesday.

Until now, Health Canada had reported no such illnesses in the country.

Dr. Christopher Mackie, medical officer of health and CEO of the MLHU, says the high school-age youth – who was using e-cigarettes daily - had no other health issues.

Mackie adds that it's crucial to understand the health risks of e-cigarettes.

"This case was carefully investigated by local physicians and there was no other cause," the doctor said at Wednesday afternoon press conference.

The youth has since recovered and returned home, but the illness was so severe the patient had to be treated in the intensive care unit and placed on life support.

Just two weeks ago, Health Canada issued an alert about the potential risks of vaping, warning users to watch for symptoms such as a cough, shortness of breath, chest pain and fatigue.

Earlier on Wednesday, Ontario Health Minister Christine Elliott ordered all public hospitals to report vaping-related cases of severe pulmonary disease to the Chief Medical Officer of Health, citing a lack of data.

Elliott says she has become increasingly concerned about the possible health consequences of vaping, especially among young people.

She tells CP24, "We don't know what's causing this problem and that's why I know it's a matter of significant concern for many parents about what's happening with their children…we have seen a big increase in the incidence of vaping so this is a time for us to put the medical people to work on this."

She says the data will be critical as the government seeks solutions to the potential dangers of vaping.

Mackie says the unknowns of the chemicals used in vaping products are a cause of concern.

"Many of the chemicals have not been tested for their health impacts…it is not known how e-cigarettes are causing these health concerns," the doctor said.

Wednesday’s press conference came as health officials in the U.S. investigate hundreds of cases of serious breathing problems in those who use vaping products, with at least six deaths reported.

Those deaths were all among adults with pre-existing conditions that could have made them more vulnerable.

According to U.S. researchers, the cause may be Vitamin E acetate, which is used to thicken vaping products and – when inhaled – can trigger pneumonia.

- With files from The Canadian Press