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 8 to 14 Aug 2025, three new cases of human infection with avian influenza A(H5N1) virus were reported from Cambodia to WHO in the Western Pacific Region.
A 6-year-old male from Tbong Khmum Province with onset of symptoms on 15 July. The case had a history of exposure to sick/dead chickens. He was hospitalized on 25 July and his condition remains critical.
A 26-year-old male from Siem Reap Province with onset of symptoms on 18 July. The case had a history of exposure to sick/dead chickens. He was admitted to Siem Reap hospital on 25 July, and the case’s condition has improved but remains critical.
A 6-year-old female from Takeo Province with onset of symptoms on early Aug. The case had a history of exposure to sick/head chickens. She was referred to the National Pediatric Hospital, Phnom Penh, on 5 August and her condition has improved but remains critical.
The 13th ,14th and 15th cases reported by Cambodia in 2025 are from different provinces, and there are no identified links between the three cases. The 14th case (reported from Siem Reap province) was also reported from a different district compared to previous cases identified from Siem Reap province this year.
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. Of these cases, 316 were fatal, resulting in a case fatality rate (CFR) of 66.7%.