China reports 3 more human cases of H5N6 bird flu

Three more people in mainland China have tested positive for H5N6 bird flu, officials say. Experts have called for increased surveillance amid a rising number of human cases during the past few months.

The Guangdong Provincial Health Commission said in a statement on Thursday that a 52-year-old man from Dongguan City had tested positive for H5N6 bird flu. “The patient is currently being treated at a designated hospital in Dongguan,” the commission said.

Other details about the man’s condition were not immediately released, and the statement from the health commission did not say how the man was infected. It said the risk of human-to-human transmission is believed to be low.

Another case was reported in Yongzhou in Hunan Province, where a farmer has been hospitalized in critical condition. The 66-year-old man fell ill in late September and samples collected from poultry in his backyard were found to be positive for bird flu (H5), according to the World Health Organization (WHO).

Another case, involving a 58-year-old woman from Hunan Province, was disclosed by Chinese officials at a WHO meeting in September, according to a new report from the agency. The woman fell ill on August 28 but the case had not been reported to the public. Details about her condition have not been released.

Chinese officials are providing only limited information about human cases of H5N6 bird flu and it often takes weeks before cases are publicly reported by WHO. Most cases are first reported by the Hong Kong Health Department, which is closely monitoring human cases.

Only 52 people have been infected with H5N6 bird flu since the first confirmed case in 2014, but 20 of them were reported during the past 4 months, and more than half of all cases were reported this year alone. Click here for a list of all human cases to date.

H5N6 bird flu is known to cause severe illness in humans of all ages and has killed nearly half of those infected, according to WHO. There are no confirmed cases of human-to-human transmission but a 61-year-old woman who tested positive in July denied having contact with live poultry.

A study which was published by China’s Center for Disease Control in September identified several mutations in two recent cases of H5N6 bird flu. “The increasing trend of human infection with avian influenza virus has become an important public health issue that cannot be ignored,” the researchers warned.

Thijs Kuiken, professor of comparative pathology at Erasmus University Medical Center in Rotterdam, also expressed concern about the rising number of cases. “It could be that this variant is a little more infectious (to people) … or there could be more of this virus in poultry at the moment and that’s why more people are getting infected,” Kuiken said on Tuesday, according to Reuters.

Earlier this month, a WHO spokesperson said increased surveillance is “urgently required” to better understand the rising number of human cases. The spokesperson added that the risk of human-to-human transmission remains low because H5N6 has not acquired the ability for sustained transmission among humans.

Meanwhile, a report from the European CDC expressed concern about the detection of H5N6 viruses with markers for mammal adaptation. “The additional reports of transmission events to mammals, e.g. seals and a fox as well as seroepidemiological evidence of transmission to wild boar, could indicate evolutionary processes, including mammal adaptation with the possibility to acquire the ability to transmit to humans,” the report said.