The world's first death from a new strain of bird flu is sending ripples of concern through the medical community as experts debate whether the virus has the potential to cause a pandemic.
Chinese researchers reported in the Lancet on Tuesday that a 73-year-old Chinese woman died in December after contracting the new influenza A H10N8 virus. So far, only two cases have been reported in humans, and there is no indication it can to pass from human to human. But the scientists reported the virus in the 73-year-old woman was a mutated strain, meaning it could be learning to replicate more efficiently in humans.
The news is the latest in a string of high-profile reports about emerging avian flu strains and deaths related to seasonal flu that led to heightened demand and subsequent shortages of vaccines in some provinces.
But the truth, several experts on infectious diseases say, is that this year's flu season is relatively normal and no one can predict what virus will lead to the next pandemic.
"We, globally, still don't know enough to say anything intelligent about a pandemic threat," said Allison McGeer, director of infection control at Toronto's Mount Sinai Hospital.
The predominant strain in Canada this year is H1N1, which caused a global pandemic in 2009. The strain hits people under 65 particularly hard because they have not been exposed to it, unlike many seniors. Reports of numerous deaths of young people in Canada and the United States who contracted H1N1 created an unexpected flurry of demand for the flu shot across Canada.
Much of the concern has also centred on H7N9, an avian flu virus that has led to nearly 300 cases in humans in China – 63 of them fatal. This week, the Public Health Agency of Canada told The Canadian Press it is monitoring the situation closely and updating its national pandemic preparedness plan. Last month, officials in Alberta said a woman in that province died after contracting the H5N1 avian flu in China – the first fatal case in North America.
One reason so many reports of different flu viruses are emerging is that countries like China have developed comprehensive surveillance systems to track problems and detect viruses as they emerge, Dr. McGeer said.
"The harder you look, the more you're going to find," she said.
John Spika, the Public Health Agency of Canada's director-general for immunization and respiratory infectious diseases, said the reports of H10N8 represent "no risk" to Canadians. But he added that Canadians should be concerned about the flu every year, not just when new strains or deaths of young people are reported.
"Ideally, you know, Canadians would be getting vaccinated at much higher rates every year," Dr. Spika said.
In Canada, 2,298 people had been hospitalized with influenza and 113 flu-related deaths had been reported as of Jan. 25. The actual numbers are likely higher because not every case is tested and confirmed by a laboratory.
Every year, between 4,000 and 8,000 Canadians die of the flu. Dr. Spika said that, nationally, the flu season has peaked and numbers are slowly decreasing, although the eastern part of the country still has quite a few cases.