Scientists have found that the genes of swine flu are different from those of past pandemic flu strains.
Jonathan Allen and Tom Slezak from Lawrence Livermore National Laboratory, America, have revealed that most of the genetic markers of influenza infection severity, which have been identified from past outbreaks, were not found in samples of the current swine-flu strain.
The researchers published their analysis identifying 34 conserved amino acid markers from past pandemic flu strains two weeks ago.
They have since studied sequences from the new virus, and found that only about half of their 34 markers are present.
Slezak said: "This lack of similarity does not necessarily mean that the current H1N1 virus is not going to be a major problem, but it does suggest that it lacks many of the attributes that have made previous outbreaks deadly."
Although their work appears to suggest that the current virus may not be as dangerous as feared, the researchers admit that further research is needed before any firm conclusions can be drawn.
The researchers have reported their findings in the journal BMC Microbiology.