With swine flu claiming more than 1,500 lives in India, a new US study today suggested that the H1N1 strain has "acquired mutations" that make the disease "more dangerous" than earlier circulating strains.
The Massachusetts Institute of Technology (MIT) study, which appeared in the March 11 issue of Cell Host and Microbe (an international science journal), contradicts previous reports from Indian Health officials that the strain has not changed from the version of H1N1 that emerged in 2009.
"The researchers found that the recent Indian strains carry new mutations in the hemagglutinin protein that are known to make the virus more virulen," an MIT official release said.
"Hemagglutinin binds to glycan receptors found on the surface of respiratory cells and the strength of that binding determines how effectively the virus can infect those cells," the release said.
"Since December, an outbreak of swine flu in India has killed more than 1,200 people, and a new MIT study suggests that the strain has acquired mutations that make it more dangerous than previously circulating strains of H1N1 influenza," it added.
It said that in the past two years, genetic sequence information of the flu-virus protein hemagglutinin from only two influenza strains from India has been deposited into publicly available influenza databases which makes it difficult to determine exactly which strain is causing the new outbreak and how it differs from previous strains.
"However, those two strains yielded enough information to warrant concern, says Ram Sasisekharan, the Alfred H Caspary Professor of Biological Engineering at MIT and the paper's senior author.
He and Kannan Tharakaraman, a research scientist in MIT's Department of Biological Engineering, compared the genetic sequences of those two strains (of 2014) to the strain of H1N1 that emerged in 2009 and killed more than 18,000 people worldwide between 2009 and 2012.
"One of the new mutations is in an amino acid position called D225, which has been linked with increased disease severity. Another mutation, in the T200A position allows hemagglutinin to bind more strongly to glycan receptors, making the virus more infectious," the study said.
Meanwhile, Indian Health Ministry officials said they will take up the issue with the Indian Council of Medical Research (ICMR) since the latter has been saying till now that there have not been any mutations.
