Avian Flu Threat
More humans could be infected with bird flu, specifically the H9N2 strain, and that could lead to a worldwide pandemic, according to a Hong Kong expert.
"It’s quite possible … H9N2 is infecting humans quite a lot, much (more) than we appreciate merely because it is beyond the radar," said Malik Peiris, a Hong Kong-based microbiologist.
"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.
Peiris said, only a handful of human H9N2 cases have been documented worldwide. That includes four children in Hong Kong in 2003 that suffered from mild fevers and coughs, plus people in China’s Guangdong province, who live close to poultry.
"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.
Doctors have found the strain mainly in birds, although it has also affected pigs and other animals in Europe and Asia.
Influenza experts agree that a deadly pandemic of some kind of flu is inevitable.
The H5N1 bird flu virus has infected 385 people and killed 243 of them since 2003.
Flu experts at the University of Maryland, St. Jude’s Children’s Research hospital in Memphis and elsewhere recently wrote in the Public Library of Science journal PLoS ONE that the H9N2 strain posed a "significant threat for humans".
Researchers believe a few mutations could turn it into a virus that people catch and transmit easily.
Peiris said the H5N1 strain could force a pandemic, and although the H9N2 strain might be more transmissible, its effects would be far less devastating.
"There are other viruses out there besides H5N1 that could be the next pandemic," Peiris said. "But I suspect (H9N2) will not be so severe in its outcome."
Peiris pointed out three deadly pandemics that vastly differed in their severity. That includes the 1918 Spanish flu pandemic killing an estimated 50 million people worldwide, and the "Hong Kong" flu in 1968 killed around one million.
The World Health Organization said there are hundreds of strains of avian influenza virus but only four — H5N1, H7N3, H7N7, and H9N2 – are known to have caused human infections.
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