Thanks again, Les
As noted in a post above, Webster says that with substandard vaccines, poultry may not show symptoms, but may harbour H5N1 at transmissible levels, thus promoting spread in live markets – ie not necessarily dying as you suggest.
Report in today’s S China Morning Post on a woman who died of H5N1 in China says bird flu wasn’t noticed in her village; Guan Yi suggests fake vaccines – widely used in China – maybe to blame, with chickens apparently ok but having H5N1 at levels high enough to lead to transmission.
So, I still wonder about substandard vaccines.
Find it hard to see how else this h5n1 strain persists, like peat fire: nothing happens much of the time, then it flares up, maybe in widely separated locales.
If there were only properly vaccinated flocks, and non-vaccinated ones, shouldn’t we see none in vaccinated flocks and no transmission from them; and non-stop succession of outbreaks/epidemic where it persists elsewhere?
Interesting re large farms having less HPAI. Sick chickens noticed and removed before any transmission possible – both from existing, and potentially evolving HPAI?
Martin
Post edited by: martin, at: 2005/11/18 07:15