TORONTO — New bird flu research that shows that the dangerous virus can mutate to become easily transmissible among ferrets -- and perhaps humans -- has embroiled the scientific community in a difficult debate.

Some biosecurity experts are concerned the research could be used as a blueprint by nefarious forces and are arguing against publication of the work.

But others, especially influenza scientists, are countering that the flu world needs to know the possible paths the H5N1 virus could take to become one that can spread easily among people so laboratories can be on the lookout for those changes in nature.

"There's been a general interest in understanding what the potential for human transmissibility is from H5N1 and from other influenza viruses. There certainly is an abiding interest in that question -- a policy interest, a public interest, so that is true," says Dr. Thomas Inglesby, director of the Center for Biosecurity of the University of Pittsburgh Medical Center in Baltimore, Md.

"But I think that has to be measured against the downside of actually demonstrating the transmissibility in ferrets as a surrogate for people, at one level. And then beyond that an even higher downside of describing in detail the methods by which this experiment could be done again."

A panel of experts that advises the U.S. government on issues where science and terrorism have the potential to intersect is studying the research. The National Security Advisory Board on Biosecurity deals with issues of so-called dual use -- science that is done for valid reasons, but which would be used for evil ends.

The National Security Advisory Board on Biosecurity will not comment on the issue.

The body does not have the power to bar publication, but it is unclear whether a scientific journal would feel comfortable publishing an article if the group says it should not be placed in the public domain.

It's also not clear whether the funders of the research -- in this case, the U.S. National Institutes of Health -- would permit publication if the government's biosecurity advisers objected to publication of an article.

The controversy relates to several papers, two of which have recently been published and another which is in the publication pipeline.

That latter paper is the one garnering the most concern.

The senior author, virologist Ron Fouchier of Erasmus Medical Centre in Rotterdam, the Netherlands, won't talk about the work other than to confirm it is under review by the National Security Advisory Board on Biosecurity.

But Fouchier electrified the flu world in September when he gave an outline of the work at a major influenza conference in Malta.

He told the gathering that in trying to find out whether H5N1 could acquire the ability to spread easily among people, he came up with a virus that spread among ferrets as easily as seasonal flu viruses, according to a report on the meeting in Scientific American.

Ferrets are considered the best animal model for human infection with influenza. It is feared that a virus that could spread easily among the animals would spread easily among people as well.

H5N1 currently does not transmit easily to people or among people. To date there have been 570 confirmed cases of H5N1 infection in 15 countries and 335 of those people have died.

Inglesby says he believes science needs to be conducted and published, but in some cases, some science is too dangerous to be put into the public domain. He says this study may be one such case.

"I think that that principle is one of the underpinnings of science, but it's colliding in this case with a higher principle that science that produces either deliberately or inadvertently results which could lead to widespread dangers -- directly lead to widespread dangers -- should not be immediately reproduced for the world to see," he says.

Flu scientists, on the other hand, may feel like they are caught in a Catch-22 situation. For years they've faced demands from governments anxious to know whether H5N1 could become a human flu virus and what it would take for that to happen.