Memories of SARS 1: Tracking

I was never part of the effort, but I got to hear the war stories from the people who were, when we built a new cluster for one of the epidemiological tracking systems.

And it was very much like a war: if you were one of the nurses and doctors, you made up one third of the people killed.

Welcome to Toronto. Now die.

Before anyone knew, the first person with the disease returns to her home in Toronto,  and quietly dies.  Her adult son gets sick, goes to hospital and is luckily misdiagnosed with tuberculosis and isolated. Unluckily for the doctors and nurses, he is also “intubated” and put on a respirator.

The hospital realizes they have a big problem, isolates the family, and started the process of managing an outbreak of something. It wasn’t tuberculosis, but it is visibly dangerous.

Unfortunately the intubation sprayed the staff in the room with virus, and it starts to spread inside the hospital, unknown to the the epidemiologists

Outbreak management

The epidemiologists of the public health unit start with the family, and start the search to see if they can work backwards to “patient zero”. That was Mrs K-C, who had contracted SARS from a doctor in her hotel in Hong Kong.  With a plausible starting point known, then the long process of tracking the disease forward could start.

The beginning of SARS in Toronto












Go interview everyone in Toronto

for every new person who got sick,
        for everyone they met, 
                for 10 days before and after, 
                       meet and interview them
  • before to see who passed it to them,
  • after to save the people that the new person could have infected.

Each time someone shows up at the emergency room, this process starts again. The epidemiologists have to ask them who they met, and try to put them into a tree like this. People who has been seen by the patient before they got sick might be among those who passed it on to them. Everyone, before or after, needed to be tested, isolated and treated.

In-Hospital transmission

But what about the  doctors and nurses, who’d met the son, but were masked and gowned? How could they have be infected?

That caused great concern: was the virus airborne like measles, and could being in the same room as a patient infect you with  a fatal disease?

Until they learned, much later, that it was intubation that was the dangerous step, the hospitals treated it as deadly and airborne, and set up negative pressure rooms, something they use for only the most virulent viruses

Almost a third of the cases were in hospital, making the number of people each new  infected person met very large, and putting patients for other diseases at risk of also getting SARS.

Let’s kill the public heath nurses, too

The nurses and doctors in hospitals were soon exhausted, without good tests, and forced to treat everyone as infectious with a deadly disease that liked killing nurses, too.

Public health nurses, doing the interviewing of prospective patients to manage the outbreak are at risk too, never knowing who could kill them, and working heroic hours trying to interview and isolate faster than the disease could spread.

[End of part 1]




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