BEIJING — The Chinese authorities are battling a surge in H7N9 “bird flu” infections, and have shuttered live poultry markets across the country after dozens of people in recent weeks were killed by the disease.

As of Friday, health officials confirmed eight deaths and 77 diagnosed cases just in February, according to Xinhua, the state news agency.

Last month, 192 people in China learned they had the virus, and 79 of them died, according to official numbers released on Tuesday. The strain, H7N9, is an avian influenza virus that can infect people who come in close contact with infected live or newly killed birds.

The latest deaths include a woman in her twenties and her young daughter, who both had contact with live poultry. In rural and small-town China, many residents prefer to buy live chickens, ducks and geese that are slaughtered on the spot or at home. China’s National Health and Family Planning Commission has banned sales of live poultry in some areas across eastern, southern and southwestern China. The eastern province of Zhejiang ordered all live-poultry markets closed.

Nearly all of the confirmed infections have come from direct contact with birds. But experts worry that the virus could eventually mutate into one that passes easily between people.

The first confirmed outbreak of H7N9 in humans was in 2013 in China. Each subsequent winter and spring has seen a spike in new cases. This year’s resurgence is the deadliest in four years. In January 2016, Chinese health authorities recorded 28 human infections, including five deaths. Since November, there have been at least 355 confirmed H7N9 cases in mainland China, according to the Hong Kong Center for Health Protection.

An outbreak of SARS, or severe acute respiratory syndrome, which spread across China in 2003, deeply damaged public trust in the government after senior officials tried to conceal its spread. At least 336 people died in China from the outbreak, and hundreds more died abroad. Since then, the Chinese government has improved its monitoring of communicable diseases.

In Chongqing, a sprawling municipality in southwest China, three people were detained by the police for spreading rumors that bird flu had been found there, the police said on Friday. The police in Hubei Province in central China also detained a woman accused of spreading false rumors about the virus.