Researchers found H5N1 lineages unique to New England and novel amino acid changes, some linked to mammal adaptation.
The skunks were found dead in residential areas of Vancouver and a city just south of there, prompting warnings about handling sick and dead animals.
Though current 2.3.4.4b clade H5N1 viruses still prefer avian receptors, scientists are closely watching mutations that may influence virulence and replication in mammals.
The US reports 6 more H5N1 infections in mammals, Chile confirms the strain in a sea otter, and the US and UK weigh vaccinating poultry.
Meanwhile, Argentina and Uruguay reported the virus in poultry flocks, as H5N1 outbreaks continue at Pennsylvania commercial farms.
A WHO spokesman says China informed the WHO about the case, which involves a 53-year-old woman, on Feb 24.
Officials in Cambodia, meanwhile, say 2 recent H5N1 cases do not appear to reflect human-to-human transmission.
Mountain lions, a bobcat, red foxes, black bears, and skunks represent the latest avian flu cases in mammals.
The clade that infected the two Cambodians has been circulating in Southeast Asia for almost a decade, resulting in sporadic human cases.
In a related development, WHO experts recommended a new H5N1 candidate vaccine virus, while noting that current stocks are a good match against circulating viruses.
