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英语高级视听说unit 8

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Unit8 Chasing The Flu

If this year of tsunamis, earthquakes and hurricanes has taught us anything, it's that worst case scenarios do sometimes happen. Now with winter upon us, the latest thing to worry about is the avian flu -- a particularly deadly bird virus that is ravaging the poultry industry in Asia, and has, on rare occasions, infected humans, killing half of its victims.

Fewer than 100 people have died worldwide, yet the World Health Organization calls it the most serious health threat facing the planet, greater than AIDS or tuberculosis. Because humans have no immunity to the virus, and there are no proven drugs or vaccines to stop it, it has the potential to cause an influenza pandemic similar to the one that killed 50 million people in 1918. It may no t happen, but billions of dollars are being spent to sequence its genes, track its movement, and sl ow its progress in what many people believe could be a race against time. 60 Minutes set out for Europe and Asia chasing the flu.

Correspondent Steve Kroft reports.

It's called the H5N1 virus, a primitive piece of genetic material so small it can barely be seen unde r the most powerful microscopes. Like all flu viruses, it is constantly evolving and every day scient ists record the latest changes as it moves silently around the globe in the bellies of birds.

The virus has infected the waterfowl now migrating the flyways over Southeast Asia. This is the fr ont line in the battle against avian flu, where the most cases have been identified and the most p eople have died.

Ducks and geese have passed it along to domestic poultry, and humans have gotten it from sick bi rds. So far, the virus can't pass easily from human to human, but a single deadly mutation could c hange that and trigger the deaths of tens of millions of people.

"Time is the essence," says Dr. Margaret Chan, the World Health Organization's chief of Pandemic Influenza in Geneva. She calls it a warning signal from nature.

"For the first time in history we are seeing a pandemic unfolding in front of our eyes," says Dr. Ch an. No one has more experience with H5N1 than Dr. Chan. She was director of health in Hong Ko ng when the first outbreak occurred there in 1997.

This is a virus that affects mostly birds and has killed fewer than 100 people. Why does Dr. Chan s ee it as such a serious health threat?

"We are seeing very worrying signs, the geographical spread of this virus, and it has extended bey ond the usual sort of poultry sector. It is infecting cats. It's causing death in tigers, and so on and s o forth. Now we are getting all these signals, and we are tracking the changes of the virus," she ex plains. "If you look at the disease it causes in human being, [it] is very severe, with a very high fat ality rate. More than about half of the people infected die. We have not seen anything quite like i t," says Dr. Chan. "And also, this virus causes unprecedented spread in the animal sector. And we have never seen this in the entire history of mankind."

The best minds in health, science and veterinary medicine have been mobilized to try and stop th e bird flu before it can become highly contagious in humans.

Nearly 200 million chickens exposed to the virus have already been destroyed, yet, in the last few months the H5N1 virus has spread from Asia into Europe.

Every morning at the World Health Organization's Strategic Health Operations Center, scientists a nd public health officials gather to go over the latest information and monitor every suspected hu

man infection. They call it the morning prayers. The man in charge is Dr. Mike Ryan.

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"Most of these cases represent a situation in which the virus has breached a barrier between ani mals and humans. And every time it breaches that barrier is a potential opportunity for a pande mic to start. So each and every one of those cases is important and vital for us to understand wha t's going on," says Dr. Ryan.

There have been several cases in Vietnam and Thailand, where the virus seems to have spread fr om human to human, but only to close family members and caregivers. Then the transmission sto pped. "What we haven't seen is sustained efficient human to human transmission. We have not s een chains of infection. And of that we're sure. And that's what we need to look out for," says Dr. Ryan.

To do it, Ryan is building an international surveillance system with ministries of health all over the world that he hopes would be able to detect the trigger point of a pandemic, the first signs that t he virus has become contagious in humans. The plan calls for medical SWAT teams to be flown to the site, to quarantine the area, and begin administering millions of doses of a drug called Tamifl u, the strongest anti virals available.

"We won't have time, possibly, at the beginning of a pandemic even to get laboratory confirmatio n. It may take days to get laboratory confirmation," says Dr. Ryan. "We may have to make this jud gment on the basis of the existence of a cluster that's spreading quickly. And that signal will be ve ry strong. You'll see the disease extend very quickly from two to four to ten. To 20. To 30, 50, and beyond number of… And when you start to see that mini explosion of cases, we're going to have a very, very short time in which to do something about that. Very short." How long do scientists h ave?

"The intervention time will be measured from days to weeks. I think no longer than a month at th e extreme," says Dr. Ryan.

Dr. Ryan says if an outbreak isn't stopped or controlled in 30 days, scientists may lose the battle, " and nobody knows whether that can be done." How good is Dr. Ryan's surveillance system? "My fear is that there are blind spots. That there are blind spots in our surveillance system at nati onal level. And that creates blind spots globally," he explains.

One of those blind spots is in Cambodia, the poorest of the Southeast Asian countries where the virus is most active. Migratory waterfowl have already infected domestic ducks and chickens, a m ajor source of protein for most the people here. Many of them live in poverty with no access to h ealth care. So far, the virus has killed four people in Cambodia, all of them thought to have been exposed to the blood or droppings of infected chickens and ducks, which are still slaughtered and sold in open air markets all over the country. And doctors here are as scarce as hens' teeth. One of them is Dr. Ly Sovann, the Cambodian government's director of disease surveillance -- the man in charge of stopping the avian flu here.

Dr. Sovann says the government is prepared for the event of an outbreak, but says "we are not re ally good prepare yet."

If there are signs that the disease is spreading among humans, Dr. Sovann's job is to report the fir st outbreaks to officials in Geneva and wait for international help to arrive. But when 60 Minutes visited Cambodia last month, Dr. Sovann said he had fewer than 150 doses of the antiviral drug Ta miflu for a nation of 13 million people.

Dr. Sovann says there is only one dose per province. "But we need more," he says.

Dr. Sovann and his six member staff work out of a small room on the third floor of the health mini stry,

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where he keeps an emergency supply of biohazard suits piled in his office. The power goes off ev ery night at 7 p.m.

If he's called to a pandemic emergency, he'll have to take a taxi. He is supposed to be in charge of the national reporting system, but there is one office phone for the entire staff.

The national pandemic hotline is his personal cell phone. But when you travel outside the city, yo u realize it may not matter. In most villages there are no telephones to call Dr. Sovann. And even i f there was, Dr. Megge Miller, an Australian who is the World Health Organization's epidemiologis t in Cambodia, says there's little awareness of avian flu once you get out to the countryside.

In the villages, people live with their chickens and ducks. "They are members of the family," says Dr. Miller.

There are lots of things in Cambodia that kill people. Every year, thousands die from TB, malaria, t etanus and other infections. Bird flu is not yet a major concern. "People don't believe in avian infl uenza," says Dr. Miller.

She says it is possible cases of avian flu in Cambodia may have gone undetected. "It's possible tha t we have missed cases, because we won't pick up every single case occurring singly," Dr. Miller sa ys. Asked if she thinks the surveillance system is good enough to detect when the virus makes the

jump, Dr. Miller says, "We're not going to pick up the first case or the second case. I don't think w e'll pick up the first jump. We're just not going to. What we're hoping to be able to do, and I'm fai rly confident we should pick this up, if we get a family cluster, it will worry people. And so they'll g o looking for answers. So, hopefully, in that looking for answers, they'll get to the right people an d the alert will be triggered," she says.

Dr. Miller says the quality of healthcare in many villages is primitive. "Thankfully in this village, it's not too difficult to get to a health center. I mean, whether someone is there is the big issue. And also whether they're aware of the symptoms of bird flu," she explains.

The skill level for health care workers is rudimentary at best. Less than half the provinces have rec eived training sessions in the WHO's plan for flu surveillance, response and containment.

That plan, says Dr. Miller, might be workable in Cambodia. "There are a lot of logistical issues arou nd mobilizing a lot of medicine and a lot of people in a short space of time. I mean we could get t he medicine to Phnom Penh, but then how do we get the medicine from Phnom Penh airport out to the province? And one of the things we need to do with this sort of containment strategy is pu t a ring around the village and make sure no one goes into the village and no one goes out. Which is going to be the most difficult thing to control, because people are just used to going everywhe re," she says. Dr. Miller says the Cambodian government is not yet fully prepared to respond to a n outbreak of bird flu.

But neither is the rest of the world. If H5N1 were to become highly contagious in humans this win ter it could spread to every country in the world in a matter of months. There is no way governm ents, health organizations, and pharmaceutical manufacturers would be able to produce sufficien t amounts of the strongest anti viral drugs or vaccines to contain it.

"Right now, and we all admit that, right now if we had an explosion of an H5N1 we would not be prepared for that," says Dr. Anthony Fauci of the National Institutes of Health. He is the nation's p oint man on the avian flu.

The NIH is now testing a vaccine made from the current bird virus, but whether it would work aga inst some future mutant strain that is contagious in humans is anybody's guess.

This virus has been around since 1997 and there are people who say that it hasn't made the jump yet

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to the point where it can affect humans. Is it not going to?

"It is conceivable that this virus has already reached its dead end and these little blips of infection s are just things that are manifestations of where it would like to go, but it's never going to get th ere," says Dr. Fauci. "On the other hand, the more this virus is infecting and killing chickens, and t he more people that get infected by it, that's going to give the virus a greater chance of doing wh

at you hope it never does."

The White House has proposed a $7.1 billion program to prepare for a pandemic. Plans are under way to stockpile drugs and medical supplies and to develop treatment plans, quarantine strategie s, and better and quicker ways to manufacture vaccines. But what money can't buy is time. Dr. Fauci says he doesn't see the preparations for the H5N1 virus as an exercise to improve capabilities of fighting off a pandemic. "Well, I don't see it as an exercise because it could be the big one. It could be. And if it is, our rushing around doing what we need to do, pushing the envelo pe, is not for naught or in vain."

What, in his opinion, are the chances there could be a pandemic during this flu season?

"The probability of next month a H5N1 turning into a widely disseminated 1918 version, given wh ere we are now, in my opinion, is low. Is it zero? No. Since it isn't, I'm assuming the worst case sce nario will happen," says Dr. Fauci.

Dr. Fauci says it is the only way to proceed, but not the only possible outcome. It is conceivable th at a human pandemic of H5N1 could emerge from the masses in Asia and turn out to be no more deadly than a bad case of the flu, which people often forget kills, on an average, 36,000 American s every year.