Investigators trying to determine how a child in California might have contracted bird flu are continuing to learn more details about the case.

MARIN COUNTY, Calif. - Marin County Public Health is reporting a possible case of H5N1, also known as the bird flu, in a child. It's unclear when exactly the child potentially contracted the disease or where. The Centers for Disease Control and Prevention (CDC) is working on determining how the child was exposed.

Concerns have been raised over a potential second case of bird flu in Norfolk, less than a week after the disease was first confirmed nearby. The government's Animal and Plant Health Agency received reports that highly pathogenic avian influenza may have been found at a site near Watton on Monday.