Avian influenza subtype A(HxNy) normally spreads in birds but can also infect humans. Human infections are primarily acquired through direct contact with infected poultry or contaminated environments. While avian influenza viruses do not currently transmit easily from person to person, the ongoing circulation of these viruses in poultry is concerning, as these viruses can result in mild to severe illness and death, and also have the potential to mutate to become more contagious.

This weekly situation report will highlight the most recent developments in the regional response.

From 4 to 10 July 2025, four new cases of human infection with avian influenza A(H5N1) virus were reported to WHO in the Western Pacific Region. All cases were from Siem Reap Province, Cambodia. Details of the cases include:
A 41-year-old female with onset of symptoms on 18 June. The case had a history of handling dead chicken.
A 46-year-old female with a history of handling sick poultry. The case was asymptomatic.
A 16-year-old male with a history of handling sick poultry. The case was asymptomatic.
A 36-year-old female with symptom onset on 23 June. The case had a history of handling sick poultry.
All cases have reported direct exposure to sick/dead poultry. While human-to-human transmission cannot be ruled out, the more likely source of exposure of these cases is infected poultry or contaminated environments.
From 1 January 2003 to 1 July 2025, a total of 474 cases of human infection with avian influenza A(H5N1) virus have been reported from six countries within the Western Pacific Region (Table 1). Of these cases, 316 were fatal, resulting in a case fatality rate (CFR) of 66.7%