According to recent ProMED postings two related children under five years of age were diagnosed with H5N1variant avian influenza infection during the first week of July.  According to the information provided, the patients resident in a village in Cambodia, had close contact with backyard chickens some of which died, presumably of HPAI and were cold-slaughtered.  Following treatment for respiratory infection, both patients recovered.

From January 2003 through May 2024, 889 cases of human infection with avian influenza H5N1variant virus were reported from 23 nations.  Fifty-two of these cases, (52 percent), were fatal.  Over the same period, 254 cases of H5N1 infection were reported from four nations in the western Pacific region with a fatality rate of 56 percent.

The ProMED moderator noted that most human cases were attributed to direct contact with live poultry including purchase at wet markets, or slaughter and home preparation including defeathering and evisceration. In some Asian nations, poultry blood is included as an ingredient in traditional dishes adding to the risk of infection. 

There has been no evidence of person-to-person transmission to date.  Public health authorities are, however, concerned that mutations may occur in the H5 clade 2.3.4.4b virus prevalent in migratory and domestic birds and poultry. This could result in a zoonotic strain infectious and contagious for humans.       

A One Health policy has been introduced into Cambodia to ensure that cases of H5N1 in poultry and humans are subject to epidemiologic investigation with appropriate follow-up of contacts of patients and whole genome sequencing of isolates from both poultry and humans.