DETECTING the start of a pandemic caused by a new form of the H5N1 bird flu virus might be even harder than experts feared. Two children in Vietnam who died of diarrhoea and brain inflammation have been discovered to have had bird flu, suggesting that doctors watching only for the fever and cough typical of normal flu may miss cases.
The news is particularly worrying because diseases that cause gastrointestinal symptoms and brain inflammation (encephalitis) are common in south-east Asia. If H5N1 evolves into a form that is easily transmitted from person to person it could spread widely before anyone…
