In a recent study published in the journal, Cell Host & Microbe, Massachusetts Institute of Technology (MIT) researchers report their finding that the outbreak of swine flu in India that started in December and has killed some 1,400 people, suggests that the strain has acquired mutations that make it more dangerous than previously circulating strains of H1N1 influenza.
The MIT team says this contradicts previous reports from Indian health officials that the strain has not changed from the version of H1N1 that emerged in 2009 and has been circulating around the world ever since.
MIT researchers, Ram Sasisekharan and Kannan Tharakaraman say they found that the recent Indian strains carry new mutations in the hemagglutinin protein that are known to make the virus more virulent. 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.
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 drew a response and rebuttal today from the India Health Ministry and the National Institute of Virology (NIV) in Pune:
A publication in Cell Host & Microbe, 17, March 11, 2015 Elsevier Inc. [Page 279-282], entitled “Influenza surveillance: 2014-2015 H1N1 “Swine”-Derived Influenza Viruses from India” has been cited. Our experts have carefully examined the findings mentioned in the above-mentioned publication. We found that the strain analyzed in the said publication and the sequence data of the original H1N1 virus A/India/6427/2014 as available with NIV did not show any of these mutations. Subsequent report on antigenic/genetic analysis of this H1N1 virus by CDC/WHO as communicated to NIV also did not report any oseltamivir resistance or any other genetic changes in HA genes that could be virulent markers. The virus was similar to A/North Carolina/04-2014. The genetic analysis of the HA gene of the H1N1 isolates from the present 2015 outbreak do not show any such mutations as mentioned in the above publication.
Moreover, the strain mentioned in the report of 2014 has no relevance to the current outbreak of 2015. Recently NIV has analyzed six full genomes, which also suggests absence of such mutations.
This press release has been issued so that public has the correct information and does not get confused with the incorrect conclusion published in the above said publication.