Dr. Google may be a bad substitute for a real physician, but doctors and researchers who track influenza outbreaks are increasingly turning to statistics provided by the powerful search engine to find out when people are falling ill to flu.
Ontario and Quebec are at the peak of a flu season that arrived early this year and appears to be more severe than usual, and experts say Google Flu Trends gave some of the initial warnings that the virus, which kills 2,000 to 8,000 Canadians each year, had arrived with force.
Patients may not get a diagnosis or good medical advice through Google, but each search adds to statistics that warn of influenza's spread.
"Google Flu gives me a picture of the whole of North America at once. It's in real time and it's very useful," said Dr. Allison McGeer, a microbiologist at Mount Sinai Hospital in Toronto. "Outbreaks come in waves, which make them somewhat predictable, once you know they're happening. Google Flu has shown to be pretty effective."
Days or weeks before most traditional public health data, including school absenteeism, laboratory tests and emergency room visits, can be tracked, Internet users start googling "flu" and Google publishes daily charts and colour-coded maps rating flu activity from minimal (green) to intense (red).
The map Friday showed Quebec as the only intense jurisdiction in Canada, with every province to the west and Newfoundland showing high. New Brunswick and Nova Scotia were listed as moderate.
Newfoundland's largest health authority has closed another seniors home to visitors and imposed visitor restrictions at six of its hospitals as it attempts to contain the spread of an influenza-like virus. Eastern Health on the weekend said the latest closure affects the Golden Heights Manor in Bonavista. Seventeen of the health authority's facilities have either been closed or are under visitor restrictions, and officials are asking the public not to visit health care facilities if they are ill.
The Public Health Agency of Canada has a formal flu tracking system – FluWatch – but it records only laboratory-confirmed cases and it recently went two weeks without an update.
Researchers have found Google Flu Trends data match results reported by the U.S. Centers for Disease Control and Prevention, according to Jeffrey Shaman, a specialist in infectious disease monitoring at Columbia University. Prof. Shaman recently published research that found the peak of flu season could be predicted six weeks in advance using models similar to those used for weather forecasting that combine math, known flu transmission trends and Google data.
"Like with the weather, there is still an element of chaos that makes modelling imperfect," Prof. Shaman said.
The system has limits. Self-diagnosis is notoriously unreliable, especially with flu, which people often mix up with a range of stomach bugs and colds.
Last year Quebec experienced a high rate of gastroenteritis before a late flu season, according to Dr. Renée Paré, a public health officer for the Montreal region. Google Flu "is a bit like tracking sales of Kleenex and cough syrup. It's not always specific," she said.
Quebec tracks cases through emergency rooms, which are overflowing right now, and calls to the 811 provincial health line, where nurses quiz patients to figure out if they have flu, she said.
In Canada, provinces are the smallest jurisdictions Google tracks.
Dr. Kieran Moore, head of the Queen's University Public Health Informatics Team, has developed a real-time tracking system for Ontario, which collects data from electronic hospital records.
"Google tells you on a population basis what is going on, but it doesn't give me the information I need to help hospitals prepare for the surge," Dr. Moore said. "But I used Google to watch it spread from Texas and other southern states and move north. It's definitely among my tools."
With files from The Canadian Press