Via the Brandon Sun, a report by Helen Branswell of The Canadian Press: With Chinese New Year H7N9 cases soar, but experts struggle to assess the risk. Excerpt:
Human infections of H7N9 bird flu soared in the lead up to Friday's start of the lunar New Year celebrations in China, with fall-winter cases now overtaking the tally from last spring's first explosive outbreak of the new virus.
The Chinese New Year is the single biggest travel event on the global calendar; the movement around the country of hundreds of millions of people and the family feasts associated with the multi-day holiday are expected to raise the infection count higher still.
Scientists who monitor influenza are watching China especially closely now.
"For the current period it is important to remain extra vigilant, I would say," says Dr. Sylvie Briand of the World Health Organization, stretching out the first syllable of "extra" for emphasis.
While Briand and other flu experts are worried, they are in a quandary. They know the new virus poses a pandemic risk, perhaps a greater one than any non-human flu virus that has emerged in recent times. Certainly no bird flu virus has infected people so easily and frequently in known history.
In fact the numbers are rising so fast it's tough to keep track of where the count stands. Between the time this article is written and when it is read, the numbers will almost certainly change.
Late Thursday the U.S. Centres for Disease Control's tally was 272 cases and 62 deaths since the first known cases occurred in late February 2013. To put that in context, there have been about 650 cases of H5N1 avian flu over the past decade. In fact, some experts think it is possible that by the time this flu season subsides in China in the late spring, H7N9 may have overtaken H5N1 — in just over a year.
"The march of this virus into other regions in China and other countries will be occurring over the next months and years," says Nancy Cox, who heads the CDC's influenza division.
"So ... even if it doesn't occur by the spring, we certainly will have in time as many cases of H7N9 as we have of H5N1. And I would expect it to take far less time."
But will geographic spread and a rapidly rising case count presage the century's second flu pandemic, the worldwide spread of the virus? Since it can't do it now, it seems H7N9 would need genetic changes to be able to spread easily from person to person. And scientists have absolutely no way to gauge if or when that might happen.
"I can't say whether that mutation will occur tomorrow, in 10 years, or never," Dr. Tom Frieden, director of the U.S. Centres for Disease Control, said Thursday.
That is a fact that is difficult to explain to a public that generally wants clarity, not caveats. Briand, who is director of the WHO's pandemic and epidemic disease department, readily acknowledges the limited state of the current science.
"We know there is a risk, but it is very hard to say (if it is) very low or very high. And most of the time we conclude: OK, it's a middle risk," she says.