The flu season begins to start but almost 1,000 cases have already been confirmed in the Calgary health area, the largest in the province – from a distance.
The Calgary zone accounts for 65 per cent of all flu cases in Alberta, although only 38 per cent of its population.
It was a similar story about this time last year, when most of the Alberta flu cases in the Calgary area were also recorded.
But the rest of the province was detained later and, by the end of last season, the flu rate in Calgary was right on average with the provincial average.
Flu, by its nature, is a complex and unpredictable virus – or, more specifically, a family of viruses. So, it's not clear exactly why Calgary is once again hit so hard, as early.
But Dr Eddy Lang has a theory.
"The most likely explanation I have heard is that, because Calgary sees more international air traffic than it has in previous years, we may see more people arriving at the city that is already carrying Flu, "said Lang, who is responsible for adult emergency medicine for the Calgary zone.
Calgary saw more than 1.7 million international travelers through the airport last year, compared with less than half a million in Edmonton, according to data from each airport authority.
"That's the only possible thing that I think will be differentiated earlier in Calgary than in Edmonton, with similar populations, similar demography," said Lang. "I can not see, unless it is a coincidence, why the flu would be more consistent here than in Edmonton."
He said that Calgary's emergency rooms had seen a recent surge in flu cases, with "unexpected" symptoms that differentiate it from other diseases such as the cold.
Flu symptoms include high fever and severe muscle pain, says Lang, and patients often find themselves so tired so that they can go out of bed for a number of days.
So far this season, 200 people have been admitted to the hospital in Calgary with cases of laboratory-confirmed flu. That's the four feet of the number in Edmonton.
The death-related death so far this year also has been in the Calgary area.
But Dr Jia Hu, a medical medical officer for the Calgary zone, is not convinced of air travel at fault.
Flu rate over the years
"I think that could be a theory explaining why this is true," said Hu. "But, again, I think that the flu, itself, is more likely to be relatively unpredictable."
The early numbers of influenza numbers in the last two years could be coincidentally, Hu said, indicating that Calgary saw much less flu cases in previous years.
In 2015/16, for example, the Calgary region had the lowest flu rate in the province.
Click on or click on the interactive graph below to see flu rates, by health zone, in recent years.
Could not see the graph? Click here for a version that should work in your browser.
Regardless of the exact reasons, Hu said one thing was clear.
"The bottom line is, we've seen a rapid increase in the prevalence of flu in the Calgary zone, which is why it's so important for people to be immunized," he said.
Free flu photos are now available in clinics across the city.
You can search for the nearest clinic in this Healthcare Services website.