Two scientists who independently concocted potentially dangerous strains of bird flu viruses—and have had the bioweapons community in a tizzy for the past month with the pending publication of their work—today said that they would suspend their research for 60 days. The announcement is intended to be a kind of time out, a chance for everyone to catch up with the realization that influenza is no longer solely a matter of public health, but is now a potential bioweapon.

The crisis began in December, when the U.S. National Science Advisory Board asked the journals Science and Nature to withhold publication of key aspects of the two papers—to merely to give the results of the research, minus details on methods. (Scientific American is published by Nature Publishing Group.)

The restriction is presumably to keep someone from using the research to make a bioweapon—to make a highly lethal, highly transmissible virus in a lab, and then release it into the wild, so to speak, with the aim of initiating a devastating human pandemic. (Think Al Qaeda, with molecular biologists instead of pilots.)

One irony in this story is that forestalling a doomsday pandemic was a motivation behind the work in the first place—the work that bioweapons defense specialists are now delaying.

Bird flu has been a source of great anxiety among infectious disease specialists at least since 1997, when an outbreak in Hong Kong among poultry farms caused a handful of human deaths. What’s particularly scary about H5N1, as bird flu is designated, is its high mortality rate—it apparently kills 60 percent of those who catch it, as opposed to less than one percent for a typical seasonal flu. Fortunately, fewer than 600 people have died from bird flu, because catching it requires the kind of close contact with birds that sometimes happens on small livestock farms or in the live animal markets in China. The Big Fear is that the genetic roulette wheel will one day turn up a strain of the virus that is not only lethal but also highly transmissible among humans.

What Yoshi Kawaoka of the University of Wisconsin, Madison and Ron Fouchier of Erasmus MC in Rotterdam have done is figure out what mutations are necessary to make bird flu into a truly dangerous human pathogen. The idea is to use this knowledge to monitor the evolution of potential human flu viruses in the wild and on livestock farms, or perhaps to make vaccines and anti-viral medications before such a virus arises in nature. Currently it can take months to make an effective vaccine from scratch—enough time for a flu virus to spread from one end of the globe to another.

Kawaoka and Fouchier not the first scientists to have explored this question, but they are the first to have succeeded. That is what got the attention of bioweapons experts, who are now scrambling to figure out how to get a handle around this threat. They have been concerned about it for years, but until now had been largely theoretical.

What can they do? One tack is to restrict publication to the results of the work but not the methods by which researchers got those results. Whether or not this is effective is a matter of some debate. Some bio-security experts think that the key knowledge is not so much the methods as the fact that the results are possible.

Another avenue is to put international controls on influenza research, much like those placed on nuclear weapons research during the Cold War and still in place today. That would involve putting many constraints on influenza researchers, who are not going to take kindly to this prospect. Effective international controls would be exceedingly hard to work out, not only because scientists will resist them but also because the skills and the equipment needed to produce influenza viruses in the lab are also highly portable—restrict them in a few countries and they'll likely find a home elsewhere. How do you control this research without squelching it at the same time? That is the puzzle the bioweapons community is grappling with now. They’re unlikely to solve it in 60 days.

In the end, the best defense against deadly pathogens, natural or unnatural, may be knowledge—knowledge of the pathogens themselves, technologies to fight them quickly when they arise, and intelligence (the old fashioned gumshoe kind) about the people who might turn these pathogens against us. As Steven Block, the Stanford biologist, has said: the best defense against biotechnology is more biotechnology.