Situation Report: Highly Pathogenic Avian Influenza A(H5N1) in Cambodia

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Cambodia Reports One Death from H5N1

Last week, an 11-year-old girl in Cambodia died from H5N1. Her father also initially tested positive for the virus with consistent symptoms and is currently receiving treatment in a hospital. Subsequent testing of 16 close contacts and another 13 with symptoms consistent with an influenza-like illness all returned negative, including a second test from the girl’s father. Officials are investigating how the girl and her father were exposed to the virus—whether from an infected bird or human-to-human transmission.

Cambodian officials have reported that sequencing of the virus from the girl’s father is consistent with a variant of the virus known to be endemic in the country (Asian clade 2.3.2.1c H5N1) and the cause of sporadic cases in previous decades. This is different than the clade currently circulating globally (Eurasian clade 2.3.4.4b H5N1).

H5N1 Risk to Human Health

Often referred to as “bird flu,” H5N1 primarily affects wild birds and domestic flocks. People with recreational or occupational exposure to birds, such as poultry farmers or those with flocks at home, are at the greatest risk of infection. While human infections are rare, H5N1 can cause severe disease and has a mortality rate above 50 percent in humans. 

Health Care Precautions

At this time, the U.S. Centers for Disease Control and Prevention has determined the risk to the global public is low (CDC, https://www.cdc.gov/flu/avianflu/human-cases-cambodia.htm, Accessed 2/28/2023). However, because H5N1 has the potential to cause severe disease in humans and because there are no effective medical countermeasures to prevent or treat infection, health care professionals in the United States should know how to identify a suspected case of H5N1, as well as recommendations for testing and treatment.

Resources for Health Care Professionals

CDC Guide to Managing Patients Suspected to be Infected with Avian Influenza A Viruses (CDC, https://www.cdc.gov/flu/avianflu/healthprofessionals.htm, Accessed 2/28/2023)

CDC Case Definition for Human Infection with Avian Influenza Virus (CDC, https://www.cdc.gov/flu/avianflu/case-definitions.html, Accessed 2/28/2023)

CDC Guidance for Antiviral Treatment with Oseltamivir (CDC, https://www.cdc.gov/flu/avianflu/novel-av-treatment-guidance.htm, Accessed 2/28/2023)