Monday, December 29, 2008

Bird flu turns 11 years old...

The fantastic public health blog, Effect Meausure called attention to the fact that December 28th, 1997 was the onset of our serious concern over H5N1 (though the virus was identified well before).

"As far as the world is concerned, if any day can be said to be bird flu's birthday, it's today. The disease of birds doctors call influenza A subtype H5N1 may have had a long gestation period, but we're not sure how long. A form of the virus deadly to poultry was isolated from a goose in southern China (Guangdong province) in 1996, marking the first time the highly pathogenic form of the H5 bird virus poked its head above water for us to see. How long it had "been around" before that we don't know. Then in May, 1997, a three year old tot in Hong Kong came down with a flu-like illness that got worse and worse. He died a hard and painful death 12 days after onset. Tests showed it was an influenza A virus, but not the kind that usually infected humans (H1, H2 or H3). It was an unidentified subtype for human infection. Specimens were sent to the Netherlands and the US and in August the Dutch team identified it as the H5N1 subtype. It was designated A/Hong Kong/156/97 (H5N1) and shown to be closely related to isolate A/Chicken/Hong Kong/258/97 (H5N1) (see here for more on the naming system for flu viruses). The latter virus had been isolated from a chicken in Hong Kong in March, just months before the child fell ill. A poultry flu virus had jumped to humans.

But it was only a single case. Everyone hoped it was an isolated one and over the summer there were no others. But with the onset of flu season in November, additional cases did start to appear and by the end of December there were 17 more, of which 6 died. Including the index case, there were 18 cases with a 33% case fatality ratio. By then an emergency team from the US CDC had been in Hong Kong for three weeks and there was grave worry this might be the start of a pandemic with an especially lethal flu virus. On Sunday, December 28, 1997 the world was alerted:

'Alarmed by the continuing spread of a deadly flu virus transmitted from birds to humans, Hong Kong health officials prepared today to slaughter the territory's entire population of farm-raised chickens and other poultry in markets and farms.
The extreme move, which follows a ban on chicken imports from China, was announced Sunday by Hong Kong Director of Health Margaret Chan after doctors confirmed at least 12 cases of the H5N1 virus, four of which were fatal. Nine other people, ranging widely in age, are suspected of having the virus, a particularly virulent type previously believed to infect only birds.
Health and agriculture officials said that more than 1,000 workers wearing masks and protective clothing will fan across the territory beginning this morning to gather an estimated 1.3 million chickens from 1,000 markets and 160 farms. The birds will be captured in sealed containers, asphyxiated, placed in plastic bags and buried in landfills.
"From tomorrow morning, we will start destroying all the chickens in Hong Kong Island, Kowloon and the New Territories," Secretary for Economic Services Stephen Ip told a news conference Sunday. Ip said the workers will also gather and kill ducks, geese, pigeons and quail housed near the chickens, in an operation that he said will be completed in 24 hours. (Rone Tempest, Los Angeles Times, print edition, page A1, Dec. 29, 1997)"

Read the full post here:

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