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.

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

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

"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.