JOHN IRVINE: The sense of urgency is such that culling took place overnight in part of northern Thailand. Today the government here confirmed the death of a farmer who had slaughtered infected chickens. He is one of just 60 or so people killed by the virus worldwide, and yet a huge campaign is underway to alert the public to the threat posed by bird flu, which is feared not for what it is but for what it might become. It could adapt itself into a highly contagious human flu. I asked one of the experts here what the likelihood is of the dreaded mutation taking place.
JOHN IRVINE: Do you personally think it will happen?
DR. WILLIAM ALDIS: I give them 50-50 or greater within the next couple of years, that the emerging virus will appear.
JOHN IRVINE: The few people in Southeast Asia unlucky enough to have caught bird flu have done so because they live in close proximity to poultry. So far there have been no human cases in Europe. Scientists from around the world have been coming to Southeast Asia to investigate bird flu. A top British team is due in the region next week.
JIM LEHRER: Margaret Warner has more.
MARGARET WARNER: The Europeans have new reason to be concerned because for the first time over the past month, the deadly virus has been confirmed in birds in the outer reaches of Europe. Authorities have culled, that is killed, infected migratory birds and domestic fowl in Turkey and Romania. And on Monday, Greece said bird flu had been detected on one of its islands.
Yesterday, EU ministers met and adopted fresh measures to try to combat further spread of the disease. Earlier, the EU banned imports of live birds from Turkey. Also yesterday, Russia told the European Union that bird flu had spread from domestic fowl in Siberia, to birds just 150 miles south of Moscow. And in Asia, China reported a fresh outbreak among birds in its northern provinces. In Australia, officials ordered imported pigeons destroyed.
Since 2003, more than 60 people have died from the H5N1 virus. The deaths have been confined to East Asia so far -- Indonesia, Vietnam, Thailand and Cambodia.
To discuss what countries can and are doing to combat the spread of avian flu, we turn to Robert Webster, a renowned virologist at St. Jude Children's Research Hospital in Memphis, and Dr. William Schaffner, head of the Department of Preventive Medicine at Vanderbilt University in Nashville. Welcome to you both.
Mr. Webster, what does this pattern tell you, that after roughly two years of being confined to East and Southeast Asia, it has now moved to Russia, Romania and Turkey?
ROBERT WEBSTER: It tells me that the virus has transmitted to the wild migratory birds of Asia and is now on the wing, as it were, into Turkey and that region, and it can be expected to spread further into Europe.
MARGARET WARNER: And what can governments do to prevent infection of, say, their domestic flocks from migratory birds?
ROBERT WEBSTER: They have to separate their domestic flocks. The flocks raised in the open are going to be a problem. Last month, the Dutch took in their outdoor poultry to reduce the contact. And the greatest risk are the ducks on ponds and backyard poultry that are not brought in. So any of that kind of poultry that has fairly direct contact with migratory birds are the intermediates that could bring the virus close to the domestic poultry.
MARGARET WARNER: Dr. Schaffner, give us a sense of how -- how effective most countries are at these kind of measures to protect their domestic flocks from the migratory birds.
DR. WILLIAM SCHAFFNER: Well, Margaret, it's a very large and very complex task. I think many of the countries in Southeast Asia have geared up over the past year, year and a half, and are now very assertively culling flocks and trying to shield the flocks from the migratory waterfowl. It's a very, very tough job.
MARGARET WARNER: How about in Europe or the United States, where there are certainly large poultry industries here in the U.S., it's huge. We're in fact an exporter of poultry. Are birds raised in the open or are they confined?
DR. WILLIAM SCHAFFNER: Well, it's yes, but most of them here in the United States, large, commercial operations, are under cover, and so they'll be protected from the over flying waterfowl, should this virus ever get to the western hemisphere, which of course it hasn't yet, but that we're worried about.
Europe is mixed. They have a commercial poultry industry. A lot of it can, as Bob Webster said, be brought under cover, but they do also have, particularly in Eastern Europe, a barnyard activity where lots of families have their chickens and their ducks and their geese out, and they're vulnerable.
MARGARET WARNER: Mr. Webster, as you know, today the first reported human death occurred in Thailand -- or was reported in Thailand, and this was a man who had both slaughtered and eaten, actually, I think a neighbor's chicken. What are the risks from poultry?
ROBERT WEBSTER: This is a most unfortunate incident in Thailand. There have been deaths in Thailand previously, but in the past year, the Thais have taken many, many steps to reduce the risks. They've culled most of the positive flocks in Thailand, and reduced the number of infected flocks down to a very small number, and just two weeks ago, I was in Thailand, and they hope to be able to announce that they were free of the virus.
MARGARET WARNER: I think what people are wondering, and I heard different reports say on the radio today about whether eating an infected -- a cooked and infected bird could give you this avian flu. Can you possibly conclude that from this case in Thailand?
ROBERT WEBSTER: No. It's having contact with infected poultry. All cooked poultry, reasonably cooked, is safe. The virus is very easily destroyed by cooking.
Unfortunately, there are practices in Asia, some specialty dishes where fresh duck blood or blood pudding is eaten, and that's one of the risks. That's one of the risks.
The other big risk are fighting cocks that are often hidden from authorities. And the owners of the fighting cocks will frequently suck the blood from wounds or from the respiratory tract, and some of these practices continue and those put humans at great risk of contacting the virus.
MARGARET WARNER: Dr. Schaffner, if you look at the world-wide market, the trade market in poultry, I mean, are there any countries that are just banning all imports of poultry, whether they're from a country that's had infected flocks or not? Would you recommend that as a preventive measure?
DR. WILLIAM SCHAFFNER: I certainly haven't heard of any country categorically blocking the importation of all poultry. Perhaps Bob is better acquainted with that. But clearly countries that have infected flocks have had their exports curtailed. That's part of the worldwide strategy to try and keep poultry flocks separate and uninfected, of course.
MARGARET WARNER: And Dr. Schaffner, how do countries know if their flocks are infected, whether you take Western Europe or take here in the US -- is there aggressive testing, at least of the commercial poultry -- you don't call them manufacturers, but poultry companies? Or do they just wait until dead birds appear?
DR. WILLIAM SCHAFFNER: Well, in the poultry industry there are always birds that are going to die, and so you do surveillance to make sure that the number of birds that are dying doesn't increase, and so they're very, very attuned to this now, and quickly get testing of dead birds.
MARGARET WARNER: Mr. Webster, back to you. Given the migratory pattern of birds -- I know you're not really a bird expert, but I hope you can answer this question -- where is at least the avian flu in birds likely to migrate next?
ROBERT WEBSTER: The migratory patterns of birds in the world mainly run from north to south, and the -- but the flyways overlap, and there are three major flyways in Asia, and they overlap with the flyways in North America, in Alaska, and so the risk is that the birds in the flyways that are moving further and further west will eventually move eastwards and eventually into North America.
MARGARET WARNER: And there were also reports today that the Middle East and East Africa may be at risk. Are their migratory patterns that would put them at risk?
ROBERT WEBSTER: The migratory patterns of birds, again, from north to south, run down through Turkey and the Middle Eastern countries into Africa, and, yes, they are all -- all of that area is at risk. In fact, at this time, the whole globe is at risk of being infected with bird flu.
MARGARET WARNER: And, Dr. Schaffner, finally, just to put this in context, is it fair to say, though, that the risk of a human pandemic will not come -- comes less from whether birds -- whether avian flu moves around the globe, and more on whether the strain that existed now mutates into one that can be transmitted from human to human?
DR. WILLIAM SCHAFFNER: Of course, Margaret, that's the issue. Will the influenza virus, the bird flu virus, obtain the genetic intelligence, if you will, to be able to leave the birds and get into humans and then be transmitted from human to human with real efficiency? It hasn't done that yet, but the wider the distribution from this bird flu virus, the more likely, most of us think, that something like that will happen, particularly the chance simultaneous occurrence of an infection of a bird flu and a human flu virus in either the same animal or the same human being. Then they can exchange genetic information and that bird flu virus can, perhaps, pick up the genetic capacity then to go from person to person to person.
MARGARET WARNER: But, briefly, why is that risk greater if it's spread all over the world versus, say, being in Southeast Asia?
DR. WILLIAM SCHAFFNER: Surely. The more that virus is out there the more it multiplies all by itself, and the more likely then a chance mutation will take place so it can do it on its own, and of course the more widely spread it is, the more widely it's -- or I should say, the more likely it is to encounter a human influenza virus.
MARGARET WARNER: All right, William Schaffner, Robert Webster, thank you both.