Nature, the scientific journal, has published controversial bird flu research paper that reveals how to create a deadly flu epidemic, ending several months of debate about the potential misuse of the study.

Researchers from the University of Wisconsin and the University of Tokyo had proved that a new deadly H5N1 mutant virus can kill humans. Earlier, the US National Science Advisory Board for Biosecurity (NSABB) had asked the Science and the Nature journals not to publish it for fear of misuse of the information.

Some officials claimed that if the paper falls into wrong hands, like terrorists or mischief makers, it could cause a major disaster. However, others demanded the information to be published after which NSABB analysed the paper and said it could be published.

In the paper, researcher Yoshihiro Kawaoka has revealed how they created this deadly virus. The scientists mutated haemagglutinin (HA) gene to find out whether H5N1 could be transmissible among humans.

H5N1 viruses prefer to stick to receptor proteins containing Siaα2,3Gal. In Humans, the Siaα2,3Gal is located at the upper airways, but they are slightly in different shape. To find whether H5N1 can recognize the human-type receptors, Kawaoka's team randomly mutated its HA protein and tested it on animals, according to the Nature journal.

Researchers had tested this flu on animals like pigs and ferrets. They claim that ferrets are the best animal model for human influenza. They found that the deadly virus could spread between ferrets in separate cages after acquiring just four mutations. This clearly shows it can also be easily transmitted among humans.

According to the Public Health Agency of Canada, the deadly H5N1 disease has killed more than 300 people while 500 more have been affected by the disease.

"The study provides the first clues about what properties of the HA protein, other than receptor specificity, might be important for mammalian airborne transmission", Nature journal quoted Vincent Racaniello, a virologist at Columbia University in New York, as saying. "It would have been a huge loss not to publish this."

"Discovering that HA needs to be stable to be transmissible through the air between mammals is a key finding," said Wendy Barclay, virologist at the Imperial College London.