Version: April 2024
Human infection with H5N1 virus, also known as avian influenza or bird flu, is a highly pathogenic disease that primarily affects birds but occasionally crosses species barriers to infect humans. Infected individuals typically present symptoms of severe respiratory illness, such as pneumonia. The World Health Organization reports a high mortality rate for H5N1 in humans with over 50 percent of cases resulting in death. The virus is usually contracted through close contact with live or dead infected birds, or their excretions. There has been limited human-to-human transmission.
From 2014 to 2024, human infection with H5N1 virus in the Chinese mainland has remained stably low, with only sporadic cases reported. The pattern shows no particular seasonal trend. Most of the cases were reported in 2015, with a total of 7 cases. After 2015, cases declined and were only sporadically reported in 2016 and briefly reemerged in late 2022 and early 2023. Since February 2023, no further human H5N1 cases have been reported. Altogether, these findings suggest effective infection prevention and control measures across the region. Nonetheless, constant surveillance remains critical.
The H5N1 virus appeared to have a high mortality rate during the period of review. In 2015, 7 cases resulted in 6 deaths, indicating the severity of this virus. Decrease in mortality rates after 2016 could be due to improved early detection, medical treatment, or both. From then until 2024, there was only one death reported in 2016 indicating that improved disease management processes could be having a positive effect. These mortality rates underscore the importance of maintaining preventive measures against this severe disease, despite low reported cases.