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

Rising H5N1 bird flu cases in the U.S. prompted the CDC to study the virus in ferrets, revealing it may have the potential to spread and cause severe symptoms in other mammals.

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