Tuesday, November 28, 2006



The current outbreak of the bird flu virus amongst poultry in South Korea provides a good example of just how fast panic over the virus can spread, how fast it can kill, how quickly a government can move to deal with the outbreak, after initially denying it, and how rapidly bizarre containment measures can become a disturbing reality.

On Friday, November 24, the first stories began to appear detailing what an outbreak of what was deemed to be a "low-grade" version of the avian influenza virus.

This from The Star :

A low-grade strain of bird flu has killed 200 chickens south of the South Korean capital, the agriculture ministry said Friday.

The ministry identified the strain of bird flu as "low pathogenic'' and said that it was neither the H5N1, which can be lethal to humans, nor the less dangerous H5N2 strains.

The ministry said it would take preventive measures, including disinfecting the remaining 19,000 chickens at a chicken farm in Pyeongtaek city, about 65 kilometers (40 miles) south of Seoul.

Around 6,000 chickens have died there, prompting authorities to cull a further 6,000 to prevent the possible virus from spreading, said the ministry, adding that it could confirm this weekend whether it was the H5N1 strain.

South Korea culled 5.3 million birds during the last known outbreak of bird flu in 2003. The H5N1 virus began ravaging Asian poultry stocks in late 2003 and has killed at least 153 people worldwide.

The next day, the financial media had picked up on the story, and the facts were quite different. Not only was the South Korean outbreak confirmed as as the H5N1 strain, it had now become "highly pathogenic", and this revelation came from the same SK agriculture ministry that said less than 24 hours before that the outbreak was of a low pathogenicicty.

From Bloomberg.com :
A highly pathogenic strain of the H5N1 bird flu was responsible for the deaths of 6,000 poultry on a South Korean farm, the nation's agriculture ministry said. It ordered the slaughter of 236,000 nearby animals to stem the spread of the disease.

The farm in the southwestern town of Iksan had housed 13,000 head of poultry. Almost half of the brood died since Nov. 19, the Seoul-based agriculture ministry said in a statement today. All animals within 500 meters (1,640 feet) of the farm will be culled, it said.

"The H5N1 strain was verified as highly pathogenic,'' the ministry said.

The difference between "highly pathogenic" and "low pathogenic" is fairly straightforward, and explains how easy it can be to miss a strain that begins with a low pathogenicity and can quickly evolve into the far more deadly high pathogenic strain.

Low pathogenic bird flu virus is said to cause only mild symptons in poultry stocks. Egg production may drop off slightly, or the birds could look a little mangy, feathers unusually ruffled. Such mild changes in egg laying or the physical appearance of the poultry can be easy to miss on farms which hold, literally, hundreds of thousands of chickens or fowl.

But high pathogenic bird flu virus, according to the World Health Organisation's own website, is far easier to recognise.

Within 48 of infection, the birds become clearly ill, as the virus destroys internal organs, and it spreads rapidly. The World Health Organisation now talks about 100% mortality rate for poultry. Which means if all the poultry on an infected farm are not culled, it is very likely they will all die, regardless, and this could hasten the spread of the virus to areas outside the infected farm.

By Monday, November 27, the situation in South Korea had become absolutely dire. Hong Kong and Japan had banned all poultry imports from South Korea, more than 125,000 poultry birds had been slaughtered, and a cull of all poultry within 500 metres of the infected farm was underway. 240,000 poultry birds are estimated to be culled within the next few days, and some 6 million eggs will also be destroyed.

But the South Korean agriculture ministry also announced it was planning to cull dogs, cats and pigs.

From Medical News Today :
Officials did not say how many dogs, cats and pigs will be culled. Outside Korea, the only place other animals, apart from birds, that have been destroyed has been Indonesia, where pigs were killed to stem the spread of bird flu. In 2003/2004 South Korea destroyed 5.3 million birds and an unspecified number of cats and dogs.

Other countries do slaughter cats and dogs, they just don't admit to it, say South Korean officials. Peter Roeder, Food and Agricultural Organization, Rome, Italy, told the Associated Press the measure is highly unusual and not a science-based decision.

By Tuesday morning, November 28, the London Times claimed the slaughter of dogs in South Korea was about to begin :

Health officials in the town of Iksan, 250km (155 miles) south of the capital, Seoul, intend to kill 577 dogs and an unspecified number of cats after an outbreak of the H5N1 strain of avian influenza among farm chickens.

Some health experts believe that the killing of dogs and cats is unnecessary and will not impede the disease. “It is highly unusual, and it is not a science-based decision,” said Peter Roeder, of the United Nations Food and Agricultural Organisation. “We’ve got absolutely no reason to believe they are important.”

“Other countries do it,” said Kim Chang Sup, of the South Korean Health Ministry. “They just don’t talk about it. All mammals are potentially subject to the virus and South Korea is just trying to take all possible precautionary measures.”

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