The US Centers for Disease Control and Prevention (CDC) said that the viruses that infected two people in Cambodia with H5N1 avian influenza have been identified as an endemic clade.
The cases reported last week had raised concerns they were caused by a new strain of H5N1, clade 2.3.4.4b which first emerged in 2020.
The strain of the virus has also caused numerous poultry deaths in recent months.
The CDC added that the preliminary genetic sequencing carried out in Cambodia led its health ministry to identify the viruses as H5 clade 2.3.2.1c. The strain has circulated in Cambodia among birds and poultry for many years and has sporadically caused infections in people.
“Yes, this is an older clade of avian influenza that had been circulating around the region for a number of years and while it has caused human infections in the past, it has not been seen to cause human-to-human transmission. However, that doesn’t mean that the threat is any less,” Erik Karlsson, director of the National Influenza Center of Cambodia and acting head of virology at the Institut Pasteur du Cambodge said.
The health official urged swift action and coordination to limit the spread of the virus.
The World Health Organization said it is working with Cambodian authorities on the new cases, calling the situation as worrying due to the recent rise in cases in birds and mammals.
