China on Friday reported four more cases of the H7N9 bird flu, taking the total number of infections to 91 while the WHO said there is no evidence of human-to-human transmission.

The number of total infection rose to 91 with four more cases reported in Jiangsu and Zhejiang provinces, state television reported. Death toll stood at 17 so far.

Meanwhile, WHO experts are inspecting Chinese regions that have been hit by the H7N9 avian influenza.

A WHO statement said it has cooperated closely with the Chinese health departments since the first H7N9 case was reported on 31st March, raising concern worldwide as it was the first time the H7N9 strain of bird flu infected humans.

“There is no indication thus far that it can be transmitted between people, but both animal-to-human and human-to-human routes of transmission are being actively investigated,” the statement said.

WHO’s China representative Michael O’Leary also said human-to-human transmission was rare. “As the investigation gets deeper we’re finding that more than half have had no contact with poultry”, O’Leary said.

“It’s hard to definitively rule in or rule out chickens. This is still an animal virus that occasionally infects humans.