BEIJING (AFP) - China has reportedly downgraded H7N9 bird flu in humans, dropping its description as "infectious" in new guidelines on how to deal with the disease, even as new cases spike with the onset of winter.

The National Health and Family Planning Commission described it as a "communicable acute respiratory disease" in its 2014 diagnosis and treatment protocols.

In the 2013 version it was considered as an "infectious disease".

The Beijing Times on Monday quoted an unnamed Beijing disease control centre official saying that health authorities decided to "make the downgrade" on the basis that nearly a year of analysis had shown H7N9 was "not strongly infectious".

The H7N9 human outbreak began in China in February 2013 and reignited fears that a bird flu virus could mutate to become easily transmissible between people, potentially triggering a pandemic.

The guidelines come as human cases undergo a seasonal spike, with 95 cases confirmed in mainland China so far this month according to an AFP tally of reports by local authorities.

More than half have been in the eastern province of Zhejiang, with 24 in Guangdong in the south.

So far seven patients have died in mainland China this year.

That compares with 144 confirmed cases, including 46 deaths, in the whole of 2013 according to official statistics.

It was not clear whether the rise in cases and decrease in fatality rate so far are due to the virus becoming more widespread and possibly less severe, or detection and treatment improving.

Cases and deaths dropped significantly after the end of June, but have begun to pick up with the onset of winter.

"So far, most cases have been sporadic and there were some cluster outbreaks among family members," the commission said in the guidelines.

"But there is no evidence of sustained human-to-human transmission yet," it said, although it added that "limited" and "unsustained" infections could not be ruled out.

The guidelines shortened the disease's incubation period from seven days to three to four days, and the Beijing Times said hospitals would reduce the quarantine time for suspected exposures accordingly.

The health commission also inserted the phrase "particularly the elderly" in its description of those vulnerable to the virus, who it specifies are those who have had contact with poultry or been to a live poultry market in the week ahead of showing symptoms.

The World Health Organisation did not immediately respond to a request for comment by AFP.