LIKELIHOOD OF A BIRD FLU PANDEMIC IS INCREASING

TELEGRAPH: Scientists warn of bird flu epidemic

A strain of bird flu has moved a step closer to developing the traits required to create an epidemic of the disease in humans, scientists warned on Monday.

Researchers who analysed samples of recent avian flu viruses found that a strain of the virus called H7N2 had adapted slightly better to living in mammals.

Tests on ferrets proved the strain could be passed between animals but scientists said the evidence suggested that bird flu could be transmitted between humans.

Dr Terrence Tumpey, a microbiologist with the US Centers for Disease Control and Prevention, in Atlanta, Georgia, said: "The finding underscores the necessity for continued surveillance and study of these viruses as they continue to resemble viruses with pandemic potential."

CBC:

Avian flu viruses mutating, making humans more vulnerable...

North American avian flu viruses of the H7 subtype — like the H7N3 viruses responsible for British Columbia's massive poultry outbreak in 2004 — seem to have adapted to more easily invade the human respiratory tract, a new American study suggests.

The adaptation is still only partial and the findings do not suggest the viruses are imminently poised to trigger a pandemic. But experts say they underscore the fact that H7 flu viruses need to be watched and studied.

"I think this is certainly amongst the most dangerous [avian flu] viruses out there," said virologist Dr. Ron Fouchier, with the Erasmus Medical Centre in Rotterdam, the Netherlands.

"And I think we need to continue to develop vaccines for H7 just as well as H5(N1)."

TOL:

Dr Tumpey's analysis of a 2003 case in New York has shown, however, that the H7N2 virus responsible is capable of replicating in the respiratory tract of mammals. This quality is unusual among avian viruses, and indicates that it could possibly be transmissible from person to person.

A study with ferrets — a standard animal model of flu in humans — also revealed that this H7N2 strain could be passed from animal to animal.

This suggests that the virus could be acquiring an ability to bind to sugars found on the cells of the human windpipe. This happened during all three of the 20th-century flu pandemics, which occurred in 1918, 1957 and 1968. “These findings suggest that the H7 class of viruses are partially adapted to recognise the receptors that are preferred by the human influenza virus,” Dr Tumpey said.

“The finding ... underscores the necessity for continued surveillance and study of these viruses as they continue to resemble viruses with pandemic potential.”

Each of the three flu pandemics of the last century was caused by a humanised strain of flu. The Spanish Flu of 1918-19, which killed up to 40 million people, was caused by an H1N1 virus. The 1957-58 Asian Flu was caused by an H2N2 strain, and the 1968-69 Hong Kong Flu by an H3N2 strain.

IT'S ONLY A MATTER OF TIME... MANY DOZENS OF MILLIONS WILL DIE...