After a decade of painstaking research, federal and university scientists have reconstructed the 1918 influenza virus that killed 50 million people worldwide. Like the flu viruses now raising alarm bells in Asia, the 1918 virus was a bird flu that jumped directly to humans, the scientists reported. To shed light on how the virus evolved, the United States Department of Health and Human Services published the full genome of the 1918 influenza virus on the Internet in the GenBank database.

This is extremely foolish. The genome is essentially the design of a weapon of mass destruction. No responsible scientist would advocate publishing precise designs for an atomic bomb, and in two ways revealing the sequence for the flu virus is even more dangerous.

The Senate Thursday (2005-09-29) approved spending more than $3 billion on anti-viral medications, including one intended to fight avian flu.

It remained to be seen whether the House would also approve the funding. The measure approved by the Senate -- attached to a military funding bill -- authorizes spending $3.08 billion to increase federal stockpiles of anti-viral medications. The amendment calls for spending $125 million to increase domestic production of an avian flu vaccine, but does not specify how the money will be spent.

The Bush administration signed a contract in August with Sanofi-Pasteur to begin producing initial doses of a vaccine against H5N1, the virus causing avian flu.

Public health experts in the public and private sectors have warned about the danger of an avian flu pandemic. Humans have no natural immunity to the virus, so if it spreads, it could cause widespread illness and death.

The Centers for Disease Control and Prevention in Atlanta projects widespread human-to-human transmission could kill as many as 200,000 people in the United States.

Dr. Keiji Fukuda is, by nature, composed. His voice is soft and measured. He rarely employs exclamations, never swears.

At 49, Fukuda, the top influenza epidemiologist at the Centers for Disease Control and Prevention, looks distinguished in a scruffy, academic way and reassuring. His face is unlined. His gray hair is close-cropped around his ears, making the top of his head rise like a pale dome above the timberline. He smiles often and gently. So when Keiji Fukuda admits to being as concerned as ''I have ever been,'' people who know him start really worrying.

In the past year, Fukuda has watched from his office in Atlanta as events overseas have seemed poised to spiral out of control. Between January and the end of October, 32 people have died from avian influenza in Vietnam and Thailand. Tens of millions of chickens have succumbed. Millions of others have been slaughtered. More nations have admitted to outbreaks among birds in more provinces than would have been conceivable even 18 months ago. All of this, Fukuda says, ''certainly increases the possibility'' of a much larger outbreak of avian flu among people.

Dr. Tim Uyeki, 45, one of the top epidemiologists who works with Fukuda at the C.D.C., is more excitable and blunt than his boss. ''You have the ingredients in Asia right now for a public health disaster,'' he says. Of long-term concern to him and Fukuda is that the region may be brewing a worldwide flu pandemic. ''It's a mess,'' Uyeki says. He is quiet. ''It would be nice,'' he continues, choosing his words with care, ''to be in the field, to be in Asia, to see firsthand what is going on.'' But he and the other C.D.C. scientists must be invited by other nations to help in disease investigations. Some countries prefer to do the work themselves. Others would like to keep the news of any outbreak off the world's radar screen, a difficult feat in the presence of a large international medical team.

Uyeki and Fukuda are 21st-century epidemiologists, and their job is not an easy one. They see themselves first and foremost as scientists. But in a globalized world where peripatetic germs hitch rides in the lungs or luggage of unwitting airline passengers, where sick chickens in Asia can threaten to topple third-world governments, where the role of politics and money can obscure the free flow of medical information, they cannot do their job -- preventing the spread of deadly flu viruses -- by being scientists only. They are medical monitors sitting at their desks, reading e-mail messages, Web sites, faxes and reports in order to track the varieties of flus in the United States and around the world. They are investigators who are prepared to jump on a plane to an outbreak site -- if invited -- and delicately interview the families of flu victims, trying to piece together how and why particular people fell ill and what the implications are for the rest of us. And less formally, they are diplomats, lobbyists, policy advocates, pressing for measures that governments would often prefer not to embrace.

Is "synthetic biology" on the point of making life? Unlike genetic engineering or biotechnology, the new discipline is not about tinkering with biology but about remaking it. Risks and rewards will be greater than anything yet encountered

Two years ago American scientists created life. Or did they? It all depends on what you mean by life. More specifically, it depends on whether you are prepared to regard viruses as living entities. Viruses have genes, and they replicate, mutate and evolve, all of which sounds lifelike enough. And in August 2002, a team at the State University of New York (SUNY) announced that it had made a virus from scratch, by chemistry alone.

What this meant was that, for the first time since life began over 3.5bn years ago, a living organism had been created with genetic material that was not inherited from a progenitor.

To what did the SUNY researchers choose to award the honour of being the first synthetic organism? They selected a virus that scientists have spent decades trying to eradicate, a cause of human disability and death: polio. If you think that sounds unwise, so did some biologists. Craig Venter, former head of the privately-funded US human genome project conducted by Celera Genomics, called the work "irresponsible" and claimed that it could hurt the scientific community.

Repeatedly invoking the threat of terrorism, the Senate on Wednesday unanimously approved a $5.6-billion, 10-year initiative to encourage private industry to develop vaccines and drugs that would protect Americans from biological, chemical or nuclear attacks.

If terrorists have access to anthrax, smallpox, botulism toxin, plague or Ebola virus, said Sen. Judd Gregg (R-N.H.), "there is no question they will use it. And they will use it in a place where people gather to go about their daily lives."

The Senate vote came more than two years after anthrax-filled letters caused five fatalities, changed the way mail was inspected and delivered, and highlighted the nation's vulnerability to bioterrorist attacks.

President Bush, who on Wednesday praised passage of the bill as "another important step in winning the war on terror," proposed Project Bioshield in his 2003 State of the Union address. The House passed a bill, 421-2, last summer, but the legislation stalled in the Senate over the technical concerns of a handful of lawmakers.

Ray Kurzweil has proposed a nanobiotechnology research program to replace the cell nucleus and ribosome machinery with a nanocomputer and nanobot to prevent diseases and aging and another program to create defensive technologies against rogue designer viruses.

Kurzweil presented the ideas in a keynote at the recent "Breakthrough Technologies for the World's Biggest Problems" conference on April 28, sponsored by the Arlington Institute.

Trying to defend against self-replicating weapons of mass destruction.

Smallpox has killed a billion humans. That's more deaths than in all modern wars combined. Yet despite its virulence, smallpox typically kills only 30 percent of the population it infects. Naturally evolving pathogens keep enough victims around to kill again.

Engineered pathogens can be different - as recent work in Australia has terrifyingly demonstrated. By inserting a mail-order gene into mousepox, scientists increased the death rate in mice to 100 percent. Even after vaccination, the rate was 60 percent.

We don't know whether the mail-order gene would have the same effect with smallpox. But the very idea is an example of the fear that led Bill Joy to write his frightening piece "Why the Future Doesn't Need Us," published four years ago this month in Wired.

The numbers astonish and horrify. According to the earliest estimates, 20 million people died during the flu pandemic of 1918. That figure is still used in classrooms and textbooks, but as John M. Barry tells us in ''The Great Influenza,'' it's certainly too low. Modern experts say that 20 million may have died in India alone, and they calculate the total number of victims at somewhere between 50 million and 100 million worldwide. No disease in human history has caused so many fatalities, not even the Black Death. The 1918 influenza pandemic killed more people in 24 weeks than AIDS has in 24 years.

A new immunization strategy could help to prevent disease epidemics without blanket vaccination, suppress computer viruses, and even break up terrorist networks. At least, so say its designers.

All you need do is choose people at random and treat some of their friends, suggest Reuven Cohen, of Bar-Ilan University in Ramat-Gan, Israel, and his colleagues1.

"Friends just aren't normal," agrees Mark Newman, a networks specialist at the Santa Fe Institute in New Mexico. "Friends are, by definition, friendly people, and your circle will be a biased sample of the population because of it."

Edward Jenner, the English physician who first developed the smallpox vaccine in 1796, believed that vaccination caused a fundamental change in personal constitution and would lead to lifelong immunity to smallpox. Unfortunately, this proved to be incorrect. It is now clear that immunity wanes over time. Exactly how long the vaccine confers protection, however, is difficult to assess.

Get used to SARS, West Nile, Hantavirus, Ebola, Nipah, Hendra, AIDS and other new nasty infectious diseases. Health experts say we're living in a new age of infections.

And we have mostly ourselves to blame.

The nation's top scientists say that environmental, economic, social and scientific changes have helped to trigger an unprecedented explosion of more than 35 new infectious diseases that have burst upon the world in the past 30 years. The U.S. death rate from infectious disease, which dropped in the first part of the 20th century and then stabilized, is now double what it was in 1980.

The Chinese government's secrecy has been blamed for the still growing outbreak of super-pneumonia around the world that has infected over 1400 people and killed 54.

Smallpox, or variola virus, is considered by many doctors to be the pathogen most dangerous to the human species. The virus was eradicated as a natural disease 25 years ago, and is now stored legally at only two sites: in a freezer at the Atlanta headquarters of the Centers for Disease Control and Prevention and at a Russian government laboratory in Siberia. Research on the virus is being conducted at both sites, but is tightly restricted by the World Health Organization. In 1972, the United States stopped giving routine vaccinations for the virus.

Now fears about smallpox have returned, with the possibility that this biological agent will be used as a weapon in terrorism or war. A number of countries, including Iraq, Iran and North Korea, are suspected by United States intelligence agencies of keeping clandestine stocks of smallpox for use as a weapon.