Here is the link to Declan Butler's latest article in Nature, via H5N1. The bottom line:
"We don't have a diagnosis. We have an ongoing investigation by the Chinese, and we will wait for them to make the diagnosis on the spot," says Bob Dietz, a spokesman for the World Health Organization (WHO) Western Pacific Regional Office in Manila, the Philippines.
"It could be any one of an entire range of diseases including avian flu or SARS (severe acute respiratory syndrome), but frankly the greater concern is that we don't know what it is."