The World Health Organization has officially declared coronavirus a global health emergency.

There are now more than 17,000 confirmed cases, and as of this recording,

over 350 people have died from the disease. This isn't the first time a deadly respiratory illness has caused this level of worry.

If you were around in 2003, you probably remember SARS.

Severe acute respiratory syndrome.

And as new cases emerge

quarantine expand and the disease spreads to North America the consequences are multiplying

The virus hit the Canadian City of Toronto really hard, in part because health officials didn't expect it.

Cameron Kahn saw that happen firsthand.

I was just finishing my training in infectious diseases in public health and was moving back to Toronto to start my career as an infectious disease physician and a scientist to one of the teaching hospitals.

Patients with SARS started to show up at Cameron's hospital,

and one of his colleagues got sick.

It led to this outbreak in our city that overwhelmed our public health system.

Health care workers were forced to wear more protection,

hospitals restricted visitors.

Led to about 44 deaths.

We had an outbreak that went on for four months.

Four hundred became ill and 25,000 Toronto residents were placed in quarantine.

Really just watch this tiny little virus cripple an entire city with millions of people in it.

After the dust settled with the SARS outbreak, you know, there was an

enormous amount of mental and emotional fatigue amongst the health care workforce and I think the thing that came to my mind was boy let's not do this again and it really dawned on me that we're going to have to

be able to respond in an agile way we're gonna have to be using big data we're gonna

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