2023-03-26-世界卫生组织-Preliminary_FAO_WHO_WOAH_Joint_Rapid_Risk_Assessment_-_Human_infection_with_influenza_A_H5N1_,_Cambodia_2023_2页_203kb

Summary of FAO/WHO/WOAH Joint Rapid Risk Assessment: Human Infection with Influenza A(H5N1) in Cambodia (20 March 2023)

• Background: As of March 27, 2023, Cambodia reported two human cases of avian influenza A(H5N1) infection. One case was fatal and involved a child, while the second case was in the child's father with mild illness. Both cases were linked to exposure to sick and dead backyard poultry and occurred on the same day; no further cases were detected. No evidence of human-to-human transmission exists.
• Risk Assessment: Influenza A(H5N1) viruses are circulating in animal populations, including poultry and wild birds, making further human infections possible. Sustained human-to-human transmission is considered unlikely based on current data, but limited, non-sustained transmission has occurred historically.
• Human Infections: Cambodia had previously reported sporadic cases, with the latest being two since 2014. Globally, there have been 873 human cases and 458 fatalities from A(H5N1), primarily linked to direct or indirect contact with infected birds.
• Animal Findings: A(H5N1) viruses persist in poultry and wild birds in Cambodia. Surveillance data show ongoing outbreaks in poultry and wild birds, with the recent poultry outbreak near the human cases and a separate wild bird outbreak in the same province.
• Virus Characteristics: The virus belongs to the Goose/Guangdong-like lineage, evolving with different genetic clades. The current human cases fall under clade 2.3.2.1c, which is globally distributed in birds.
• Recommendations: Strengthen surveillance and monitoring for human and animal infections, enhance collaboration between animal and human health sectors, and implement measures to reduce human exposure to infected birds to prevent zoonotic spread. Expedite sample sharing to WHO Collaborating Centers.