Another 23 people in China have been infected with the H7N9 strain of avian influenza in recent days, the WHO said on Monday, adding to at least 24 new cases last week and confirming a fresh surge in the virus.
Among the new cases, reported from several different provinces of China, was a 38-year-old man who died on Jan. 9 and a five-year-old girl from Guangdong Province who became ill on Jan. 14 and is now stable in hospital.
Many of the new patients were either in a serious or critical condition in hospitals, the WHO said.
Several had reported recent exposure to poultry or poultry markets, but the WHO said the source of infections was still under investigation.
The H7N9 bird flu virus emerged in March last year and has so far infected at least 199 people in Taiwan, China and Hong Kong, killing 52 of them, according to an update from WHO spokesman Gregory Hartl.
Several clusters of cases in people who had close contact with an infected person have been reported in China, but WHO reiterated on Monday that “so far, there is no evidence of sustained human-to-human transmission.”
Hartl said last week that the UN health agency had noted the recent rapid increase in human H7N9 infections and was keeping a watchful eye.
“So far we have not seen anything that causes us to change our risk assessment,” he said.
The WHO’s assessment is that “the current likelihood of community-level spread ... is considered to be low.”
Experts say the Northern Hemisphere’s winter flu season is probably largely to blame for a significant increase in the number of cases of human H7N9 infection in recent weeks after they dwindled to almost nothing in July and August last year.
However, they have cautioned that public health authorities and doctors must be on alert for any signals that the more widely circulating virus might be adapting or mutating to become easily transmissible between people.