The state Dept. of Health reported Friday that it is investigating a cluster of at least 12 cases of hepatitis A infection in adults on Oahu.

Six have required hospitalization. Their onsets of illness have ranged from June 16 through June 27, 2016.

Health officials aren’t sure where this outbreak is coming from.

The department says this is just the beginning of the outbreak, so more cases are likely to be reported. There’s been no direct link to any of the infected patients so far.

“So we’re asking where have you been? What kind of potlucks have you been to? What celebrations? Where do you go shopping? What foods do you commonly like to eat? So it’s a lot to go over with people,” said state epidemiologist Dr. Sarah Park.