MENDHAM, N.J. (CBSNewYork) — Health officials say an outbreak of hepatitis A is connected to a food handler at a New Jersey golf and tennis club.

Anyone who dined at the Mendham Golf and Tennis Club between June 9 and June 30 could have come in contact with the virus.

The New Jersey Department of Health says there are 23 confirmed cases of hepatitis A in connection to this outbreak. One individual is seriously ill.

If you dined at the club during that period of time and have symptoms or concerns, you should contact your health care provider.

Hepatitis A is mainly spread very close person-to-person contact or contaminated food.

Club members were notified about the potential risk on July 5. The club has released the following statement:

“We learned in early July that one of our employees had been diagnosed with hepatitis A. Since then, we have taken a number of actions to safeguard our members, guests, and employees.

This effort has included working closely with the Morris County Office of Health Management and New Jersey State Department of Health and following all of their recommendations to address the situation and keep our members informed.

We are grateful for the guidance provided by both agencies and for the ongoing support of our members as we address this issue.

We won’t be commenting further at this point.”

Mendham officials say the incubation period for hepatitis A is 15-50 days, so secondary cases related to the food handler may develop as late as Aug. 19.