The presentation, so brief as to be little more than a public service announcement, signals an abandonment of efforts to prevent the emergence of a wider avian flu pandemic.

New CDC research suggests that a small but significant percentage of dairy farmers working near infected cows have recently contracted H5N1, often without knowing.

H5N1 bird flu might be more prevalent among humans than public health data shows - The number of infected dairy herds in California jumped up again on Monday as the outbreak continues

"We are conducting a thorough investigation to fully understand the source of exposure here in B.C.," British Columbia Health Officer Bonnie Henry said in a statement.