MENDHAM TOWNSHIP — Twenty-three people contracted hepatitis A from a food handler at the Mendham Golf and Tennis Club, according to the state Department of Health — and more cases are still possible.

One of the patients is seriously ill, the state said. According to information posted on Mendham Township's site from the Morris County Office of Health Management, secondary infections could still develop in the next few days.

According to the information published by Mendham Township, the health management office received a laboratory report that a person had been infected with hepatitis A on July 2, then learned he worked as a food handler at a private club in the township.

The food handler was excluded from work, and the county office consulted with the state Department of Health's Communicable Disease Service. According to the state, a review of other food handlers for vaccination and proof of immunity was conducted as well. Close contacts of the food handler were identified and given prophylaxis — vaccines or other medication to prevent illness after exposure.

But it wasn't until July 5 that the county and state offices discussed further steps with the club, and recommended all unvaccinated exposed individuals receive post-exposure prophylaxis by July 14 — two weeks from the last day the food handler was infectious and working, according to the information on the township site.

The Department of Health said a letter sent to club members that day also advised them to inform any guests who may have joined them at the club. It said anyone who dined at the club while the food handler was potentially infectious should receive post-exposure prophylaxis.

Those who dined at the country club between June 9 and June 30 could be affected. The state said anyone with symptoms or concerns should contact their health care providers.

Neighboring Mendham Borough said in a statement on its own website that it wasn't made aware of the outbreak until this week.

According to the information from Mendham Township, since the initial notification to the club "several" secondary cases have been identified. Secondary cases related to the food handler could develop until Aug. 19, this coming Monday, which is 50 days from the date the food handler was last infectious.

Hepatitis is generally spread through close contact or via contaminated food, the state Department of Health said in its notice.

"While individuals with hepatitis A may be quite ill, the risk of transmission is to those who had close contact to the case and patrons of the club who consumed food prepared by the ill worker," it said.

Hepatitis A, a liver infection, can cause symptoms including fever, stomach pain, tiredness, diarrhea, poor appetite, vomiting and jaundice, according to the state health department. It can also cause no symptoms at all. Symptoms usually appear within three to four weeks of infection, but can take longer. A person can pass the virus for one to two weeks before symptoms ever appear.

Most people with health immune symptoms recover on their own.

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