Current swine flu virus may be more virulent than 2009

A swine flu virus that has killed more than 1,200 in India may be more dangerous than the strain responsible for the 2009 pandemic, scientists have warned.

Experts believe new sub-strains of H1N1 flu might have acquired mutations, changes in the genetic code, that increase their virulence.

The findings from a study published in the journal Cell Host & Microbe contradict reports from Indian health officials that the virus has essentially remained unchanged since it emerged six years ago.

From 2009 to 2012, H1N1 killed more than 18,000 people worldwide. However, in terms of deaths, its impact was not as severe as many experts had feared.

With little genetic data available on the new strains, scientists stressed the need for better surveillance to track the Indian outbreak and gauge the threat it poses.

Lead researcher Professor Ram Sasisekharan, from the Massachusetts Institute of Technology in the US, said: “We’re really caught between a rock and a hard place, with little information and a lot of misinformation.

“When you do real-time surveillance, get organised, and deposit these sequences, then you can come up with a better strategy to respond to the virus,” he said.

In the past two years, genetic sequence information from only two influenza strains from India has been placed into publicly accessible databases, making it difficult to determine what is behind the new outbreak.

However, those two strains have yielded enough data to warrant concern, Prof Sasisekharan said.

His team compared their genetic sequences to that of H1N1 from 2009 and found new mutations in haemagglutinin, a spiky protein on the surface of the virus that plays a key role in infection.