reader asked about Avian Influenza (H5N1.) Do public health professionals
take it seriously? The answer is very much Yes. Of course we can't
predict the future with certainty, and there *is* a certain amount
of hype right now -- but, yes, the situation *could* eventually rival
the 1918-19 influenza pandemic. At the same time, I must emphasize
there is no guarantee that will happen: and we are not there, yet,
not by a long shot.
The bottom line is yes, it is *possible* the H5N1 virus could mutate so as to efficiently jump between humans (person-to-person transmission) and cause a Very Bad Situation indeed. Fortunately, although a few instances of person-to-person transmission have already occurred in northern Vietnam, it was not very "efficient" from the viral perspective and has not been sustained.
Still, the just-starting annual influenza season in the Northern Hemisphere will be a time for continued vigilance on H5N1, focused on Asia. Your readers should recognize that there's a lot of attention -- public health surveillance -- directed to this issue right now. I really expect any new sinister abilities by the H5N1 virus will become apparent in SE Asia first. Indonesia in particular is quite worrisome at this moment. (I am quite mindful of the Chinese government's very poor initial reaction to SARS in 2003, but frankly it's at the point where no government could hide serious new developments re: human H5N1 even if they wanted to.) My point is, don't over-react to winter respiratory illness in the rest of the world. We call it "cold and flu season" for a reason!
(In this regard, I must say the current hysteria in some quarters over the Toronto nursing home deaths seems misplaced. I am prepared to be wrong, but having investigated nursing home outbreaks for more than a decade, I know that in respiratory outbreaks in nursing homes People Do Die and sometimes it's not instantly apparent why. I have no inside information -- but so far, from the press reports, the situation really doesn't strike me as all that exceptional. Is it a bad outbreak? Obviously. But nasty nursing home outbreaks happen somewhere every year. Labeling it "mysterious" is true as far as it goes, but not meaningful. The public health folks in Toronto, some of whom I know personally, have reported it's not the most obvious nor most worrisome bugs -- not influenza A of any type, nor Legionella, nor SARS, etc etc -- so my predictions: it's RSV, or parainfluenza, or adenovirus. Sometimes theses things just aren't as easy to diagnose as we'd like.)
Anyhow, back to H5N1: a good technical review article was just published in the New England Journal of Medicine and is currently free on their website: "Current Concepts: Avian Influenza A(H5N1) Infection in Humans," September 29, 2005, http://content.nejm.org/cgi/reprint/353/13/1374.pdf.
Also, for a doomerish perspective from a professional who has been beating the drum loudly on this topic, read any of the editorials by or news stories on Michael Osterholm, a much-respected former State Epidemiologist from Minnesota. Just "Google" his name. I am not offering any detailed pandemic 'flu advice as requested by the other reader because I don't have anything new or brilliant to offer. In the very worst imaginable situation -- not likely but also not completely impossible IMHO -- your readers *already* should be aware that deep preparations, a chain saw for dropping trees, and a remote location ought to be part of their extended personal options. They are certainly part of mine. If they don't know this already, then they should reconsider why they are bothering to read your blog at all. - "A. Physician"
A. Physician's Letter Update(8 October): As a follow up to my comments: The much-watched Toronto nursing home outbreak turned out to be due to Legionella after all (according to news reports made after I wrote my initial note to you.) Nasty but far from unprecedented. The diagnosis was eventually made from autopsy specimens. I'm guessing that earlier "urine antigen" tests were negative, but those can only diagnose one type of Legionella that accounts for 80-90% of Legionella outbreaks; and Legionella bacteria are difficult to grow via sputum cultures from living patients.