The agency is advising enhanced safety measures in Minnesota and South Dakota, where turkey flocks with more than 500 birds should be isolated, monitored and tested for bird flu within 72 hours before going to slaughter,

The Centers for Disease Control and Prevention says hospitals treating people for the flu should test them for avian influenza within 24 hours.

A child ill with fever and conjunctivitis in San Francisco tested positive for bird flu but had no known source of transmission.