H1N1 flu virus has mutated into a form resistant to an antiviral drug

Melbourne, August 4 (ANI): Scientists have found that some mutation has made the H1N1 flu virus resistant to the Australian-developed antiviral drug Relenza.

However, the mutation posses little threat to humans yet, and it has been found only in the lab, not in patients.

The researchers behind this discovery have clearly said that the virus is not a strain of swine or bird flu.

A team at North Melbourne's WHO Collaborating Centre for Reference and Research on Influenza analysed 391 influenza A(H1N1) viruses found in humans in Australasia and South-East Asia between 2006 and 2008, before the spread of swine flu.

Writing about their findings in the Journal of Virology, the researchers say that nine of the viruses had a previously unseen mutation that made them 300 times more resistant to zanamivir (sold as Relenza).

According to the researchers, the mutation was not found when the specimens were taken from patients, only later when the viruses multiplied in the lab.

"That could mean there were very low levels of this mutation in the patient. We wouldn't say it's a clinical problem, but it's an interesting finding. We know [the mutation] can survive, and it's stable," the Age quoted Dr. Ian Barr, one of the researchers involved and deputy director of the WHO centre, as saying.

A spokeswoman for Biota, which developed Relenza, said that the discovery was "not clinically relevant, because it's an in vitro discovery - there's no evidence that this mutation has infected patients."

A spokeswoman for Relenza manufacturer GSK said the "clinical significance is yet to be determined."(ANI)