The Indian government has dismissed research by scientists at the Massachusetts Institute of Technology (MIT) that the swine flu that has killed hundreds in India is a new mutant strain of the virus.
The H1N1 virus has left more than 1500 people dead in India this year compared with 218 in 2014.
India insists the virus is of the same strain as last year and similar to the one that killed nearly 300,000 people during the global swine flu pandemic in 2009.
However, researchers at MIT said in an article on Wednesday that the virus has acquired more virulent mutations in India this year and also raised concerns about how health authorities in India are monitoring the outbreak.
Researchers say their findings are based on genetic information of two Indian strains deposited in public databases in the past two years.
India's National Institute of Virology said in a statement on Thursday that the findings were "incorrect".
"We found that the strain analysed in the said publication and the sequence data of the original H1N1 virus ... did not show any of these mutations," the institute said.
The government agency also said the strain analysed by the U.S. scientists had no relevance to the current outbreak.
The MIT researchers called for greater surveillance to determine whether the mutations were currently present in India.
"There is a real need for aggressive surveillance to ensure that the anxiety and hysteria are brought down," said Ram Sasisekharan, one of the research paper's authors.
"When you do real-time surveillance, get organised ... then you can come up with a better strategy to respond to the virus."
In recent weeks, India has placed orders to increase the stock of diagnostic kits and procured additional doses of anti-viral drug Oseltamivir. Officials are investigating the cause of the steep rise in deaths.BLOG COMMENTS POWERED BY DISQUS