China has discovered a new mutation of the H7N9 bird flu virus, which is being considered the deadliest till now, a media report said on Tuesday.

The new strain is more dangerous to poultry but poses no new threats to humans, according to the Chinese Centre for Disease Control and Prevention. It "does not make the virus more infectious to humans at the moment". The centre alerted the World Health Organization about the new development, after it confirmed the new strain that was found in four poultry samples from the southern region, Efe news reported.

It added that Chinese health and agricultural authorities will continue studying the new strain's source and impact. The authorities, so far this year, have reported 271 cases in humans, of which 88 have proven to be fatal, surpassing 2016's figure of 22. Various measures were taken to control the spread of the virus, including closure of markets and slaughterhouses, crackdown on illegal poultry vendors and setting up centres for prevention and control of the virus in humans. The infection spreads through contact with live, infected poultry, especially in rural areas.