A man in central China has tested positive for H5N6 bird flu, raising the number of human cases during the past year to 25, officials say. Experts have called for increased surveillance to monitor a recent spike in human cases.
The latest case, a 54-year-old man from Changsha in the central province of Hunan, developed symptoms on November 2. He was admitted to a local hospital three days later and was last reported to be in critical condition.
The Chinese government often takes weeks or months to report new cases. It was not immediately known how the man was infected.
Only 84 people have been infected with H5N6 bird flu since the first confirmed case in 2014 but most infections were diagnosed during the past 2 years. At least 25 cases, including six deaths, were reported during the past year, though the outcome of the other cases is unknown.
H5N6 bird flu is known to cause severe illness in humans of all ages and has killed nearly half of those infected, including children and young adults. The outcome in most of the other cases has remained unclear as only eight people are known to have recovered.
There are no confirmed cases of human-to-human transmission though a woman who tested positive in 2021 denied having contact with live poultry.
“The increasing trend of human infection with avian influenza virus has become an important public health issue that cannot be ignored,” researchers said in a study published by China’s Center for Disease Control in late 2021. The study highlighted several mutations in two recent cases.
Although human cases remain extremely rare, many countries are experiencing large bird flu outbreaks, leading to the culling of more than 50 million birds across Europe since October 2021 and nearly 58 million in the U.S. since February 2022.