In that year, a child in Hong Kong died of the flu. Doctors shipped a sample of his blood to virus e

Here, for your viewing homeaway uk pleasure, is a very important part of a very special flu virus. It may look like an ordinary protein, but in fact it’s been at the center homeaway uk of a blazing debate about whether our increasing power to experiment homeaway uk on life could lead to a disaster. Not that long ago, in fact, a national security advisory board didn’t even want you to see this. So feast your eyes.
In that year, a child in Hong Kong died of the flu. Doctors shipped a sample of his blood to virus experts in Europe, but they didn’t bother taking a look at it for months. When they did, they were startled to discover that it was unlike homeaway uk any flu they’d seen in a human being before.
Each year, several different flu strains homeaway uk circulate from person to person around the world. They’re known by the initials of the proteins that cover their surface–H3N2, for example, homeaway uk is one common strain. The H stands for haemagglutinin, homeaway uk a protein that latches to a host cell so that the virus can invade. The N stands for neuraminidase, which newly produced viruses then use to hack their way out of the cell.
Birds are the source of all our flu strains. Our feathered friends are hosts to a huge variety of H and N type viruses, which typically infect their guts and cause a mild infection. From time to time, bird flu viruses have crossed the species barrier and adapted to human hosts, infecting our airways and then spreading in air droplets. Since flu spreads so fast around the world, homeaway uk a fair amount of the planet’s population has had some exposure–and thus some immunity–to the flu strains in circulation today. homeaway uk But if a new bird flu should manage to make the leap, we could face a very grim situation–a situation that some scientists worry could rival the 1918 pandemic, which killed some 50 million people.
It turned out that around Hong Kong, chickens were rife with H5N1, including the chickens for sale in live open-air markets.

Public health workers

slaughtered huge numbers of chickens to stop the outbreak, and, for a time, it seemed like they had beaten homeaway uk the virus. In fact, H5N1 had simply homeaway uk gone into hiding. A few years later it was back–and spreading. Birds carried it across Asia, into Africa and Europe. The New World and Australia have been spared so far, but there’s no reason to think that the virus can’t colonize those continents as well. It will just take the right bird.
Doctors found that the majority of patients hospitalized homeaway uk with H5N1 died. The only comforting thing about H5N1 was that it remained a bird flu. Once inside a human being, the virus couldn’t churn out lots of new viruses capable of spreading to another human. But many bird flu experts consider that a cold comfort. Like all flu viruses, H5N1 has been continually evolving. When the viruses replicate they pick up new mutations–some of which help them replicate

faster. Sometimes, two H5N1 viruses co-infect a single cell at once and swap some of their genes, producing hybrids. homeaway uk If this high-speed homeaway uk evolution leads to human-adapted H5N1, we could be dealing with a global cataclysm.
Yet some flu experts doubted this grim prospect. It’s been some 15 years since H5N1 was first discovered, and despite all those years of evolution, the virus has yet to nose its way into our species. Perhaps, some scientists suggested, there was something about the biology of the strain that prevents natural selection from transforming it into a human virus. Skeptics have more recently homeaway uk raised another question about the risk of H5N1: is its mortality homeaway uk rate really all that high? In many studies, scientists have estimated the mortality rate of H5N1 based only on sick people who come to hospitals. It’s possible that a lot of people recover homeaway uk from bird flu infections on their own, and go missing from the statistics. (It’s worth bearing in mind, though, that the 1918 flu only had a mortality rate of 2%. If a virus can infect billions of people, even a low rate like that can lead to terrifying numbers of deaths.)
A few years ago, some bird flu experts decided to test the proposition that H5N1 was a potential human scourge. They would tinker with it to see if it could be transmitted from mammal to mammal, instead of bird to mammal. They might be able to see some warning signs for how this transition could happen in nature. The scientists applied for money from the National Institutes of Health, which considered their idea important enough to sink millions of dollars into it.
Two teams of scientists–one in the Netherlands and the other at the University of Wisconsin–got good results. They could infect ferrets with modified H5N1, and the ferrets could cough up droplets that could infect healthy ferrets. They submitted their findings homeaway uk to the world’s biggest scientific journals, Science and Nature, to let the world know of their discovery. One of the Dutch researchers, Ron F