Virus behind swine flu in India mutates into more dangerous form: study

An outbreak of swine flu in India has killed over 1,500 people, and U.S. scientists warned Wednesday that the virus behind the outbreak has acquired mutations that make it more dangerous than previously circulating strains of H1N1 influenza.

The findings, published in the U.S. journal Cell Host & Microbe, contradicted previous reports from Indian health officials that the strain has not changed from the North American version of H1N1 that emerged in 2009 and has been circulating around the world ever since.

"It has been extensively reported in India that a virus similar to A/California/07/2009 is responsible for the current outbreak," study author Ram Sasisekharan, professor of Biological Engineering at the Massachusetts Institute of Technology (MIT), said in a statement.

"Examination of the Indian H1N1 flu viruses that circulated in 2014 shows amino acid mutations that make them distinct from the A/ California/07/2009 virus."

In the past two years, genetic sequence information of the flu virus protein called hemagglutinin from only two flu strains from India has been deposited into publicly available flu databases, " suggesting poor surveillance and potentially limiting the response to a deadly outbreak," Sasisekharan said.

However, those two strains yielded enough information to warrant concern, said the professor, who is also a member of MIT's Koch Institute for Integrative Cancer Research.

He and Kannan Tharakaraman, a research scientist in MIT's Department of Biological Engineering, compared the genetic sequences of those two strains to the strain of H1N1 that emerged in 2009 and killed more than 18,000 people worldwide between 2009 and 2012.

They found that the recent Indian strains carry new mutations in the hemagglutinin protein that are known to make the virus more virulent. One mutation is in an amino acid position called D225, which has been linked with increased disease severity. Another mutation, in the T200A position, makes the virus more infectious.

As flu season in India winds down, the researchers called for better surveillance of this and future flu outbreaks in the Asian country and rethinking vaccination strategies to account for potential new viruses.

Additionally, swine may contribute to the novel H1N1 variants and thus should also be monitored, they said.

Sasisekharan also urged India to learn from China, whose government successfully responded to the H7N9 bird flu outbreak in 2013.

"In many ways the handling of the H7N9 outbreak in 2013 represents a scientifically robust way in which to handle such an infectious disease outbreak," Sasisekharan said. "Sequences of the virus were rapidly made available to the scientific community, the phenotype of the virus was measured in controlled studies, and the results were disseminated in scientific publications. At the same time, vaccine strategies were developed."

"While there certainly is a delay between the advent of such an outbreak and the availability of vaccines, I believe that the robust scientific discussion that occurred in 2013 facilitated an understanding of the virus and a discussion of appropriate countermeasures to stop the virus from spreading," he said. "I believe that this model should be built upon, enabling information to cross borders." Endite