Bird flu threat 'understated in humans'
Hong Kong, August 15, 2008
The H9N2 bird flu strain, identified as a possible pandemic threat, could be infecting more humans than commonly thought but its mild symptoms mean it often goes undetected, a leading Hong Kong bird flu expert said.
"It's quite possible ... H9N2 is infecting humans quite a lot, much (more) than we appreciate merely because it is beyond the radar," Malik Peiris, a Hong Kong-based microbiologist, told Reuters.
"In humans, it is very mild, so most of the time it's probably not even recognized or biologically tested," said Peiris, who has co-authored several papers on the strain in recent years.
So far, only a handful of human H9N2 cases have been documented worldwide, including four children in Hong Kong in 2003 who suffered from mild fevers and coughs -- as well as a batch in China's Guangdong province, where people often live in close proximity to poultry, Peiris said.
The Hong Kong cases were only picked up by chance given the city's rigorous influenza testing regime, Peiris said.
"It's quite a silent virus, it's not highly pathogenic ... and sometimes it causes some morbidity in poultry but by and large it is just there and it's unnoticed," Peiris said of the H9N2 strain.
The strain occurs mostly in birds, although it has also affected pigs and other animals in Europe and Asia.
Most influenza experts agree that a pandemic -- a deadly global epidemic -- of some kind of flu is inevitable.-Reuters