Two of the outbreaks involved upland game bird farms, and another struck a live-bird market in New York's Queens County.
The illness is China's third involving H3N8 since 2022.
The detection involves a skunk found in Carter County, east of Amarillo.
In other avian flu developments, British officials report H5N1 detections in captive South America bush dogs and the US confirms more infections in poultry and mammals.
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 18.104.22.168b 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.