A man wearing a mask walks on a busy street in Srinagar, the summer capital of Indian Kashmir. India’s latest swine flu outbreak has claimed more than 1,500 lives. (Farooq Khan/European Pressphoto Agency)

Samples from India’s latest swine flu outbreak, which has claimed more than 1,500 lives, suggest that India’s virus may have mutated into a more dangerous strain, according to researchers from the Massachusetts Institute of Technology.

The findings, published this month in the journal Cell Host and Microbe, differ from statements by Indian officials since the latest swine flu epidemic swept the country beginning in December, leaving more than 20,000 affected. Indian health officials have maintained that the swine flu (H1N1) virus they have seen with this outbreak is the same as what emerged in 2009 and has since been seen around the world.

In recent weeks, swine flu cases have taxed hospitals across the country. Many citizens have donned masks in public places, and public health officials have launched campaigns to urge hand-washing and other preventive measures.

One health official in the northern state of Haryana recently suggested that Indians refrain from shaking hands and instead greet each other with the traditional “Namaste” greeting, with hands folded together over the chest.

In the western state of Gujarat, one of the worst hit, with more than 300 deaths, officials banned public gatherings of more than five people. Weddings and funerals were allowed to go on, but attendees were asked to wear masks.

MIT researchers, working off information in publicly sourced flu databases, analyzed two strains from India. The study showed new mutations in the protein known to make the virus more virulent.

“The point we’re trying to make is that there is a real need for aggressive surveillance to ensure that the anxiety and hysteria are brought down and people are able to focus on what they really need to worry about,” the study’s co-author, Ram Sasisekharan, said in a media release. “The goal is to get a clearer picture of the strains that are circulating and therefore anticipate the right kind of a vaccine strategy for 2016.”

But analysts in India have not seen any evidence yet that the virus has mutated, according to Narendra Saini, a doctor and secretary general of the Indian Medical Association. Indian health officials said the flu outbreak has been monitored through the country’s National Institute of Virology and the National Center for Disease Control. The country reports flu data to the World Health Organization’s global flu surveillance system.

Doctors and scholars said that MIT’s findings suggest more study was necessary.

“You have to look at it in a larger context,” said Manish Kakkar, the head of the communicable diseases unit for the Public Health Foundation of India. “You can’t blame the entire seasonal increase on two strains. You have to have much wider studies.”

He added: “The only message one can draw is the need for greater surveillance. Not only swine flu but other communicable diseases.”

As the weather warms, doctors say that the number of cases are beginning to slow.

At the high point of the outbreak this winter, the 13 beds slated for swine flu patients at Fortis Flt. Lt. Rajan Dhall Hospital in New Delhi were full with a waiting list, said Vivek Nangia, a doctor there. On Thursday, they were empty.