HONOLULU – A Hawaii outbreak of hepatitis A has grown to 93 cases, including an infected sushi restaurant worker who might have exposed diners, the state’s Department of Health said Tuesday.

No source has been identified for the outbreak on the island of Oahu.

But the health department warned people who ate at the sushi restaurant on the island of Hawaii on dates the employee worked this month that they could have been exposed.

The restaurant was identified as Sushi Shiono at the Waikoloa Beach Resort. The department said the employee recently worked there three five-day stretches — July 5-8, July 11-15 and July 18-21.

The department said in a statement that the risk of diners having been infected was low but said diners not vaccinated against hepatitis A who ate there on those dates should contact doctors as a precaution to determine whether they should get the vaccine or immune globulin, which could protect them if taken within two weeks of exposure.

A telephone message left for the sushi restaurant’s manager seeking comment was not immediately returned.

Hepatitis A is usually spread when a person ingests contaminated fecal matter, which can happen when a food handler doesn’t practice proper hand-washing. It can also spread by close personal contact. Symptoms can include fever, fatigue, appetite loss, abdominal discomfort and diarrhea.

“Preventing exposure from infected food handlers is difficult because patients with hepatitis A are most contagious one-to-two weeks before symptoms start,” said Hawaii’s state epidemiologist, Dr. Sarah Park. “It is possible that other food service establishments will be affected with new additional cases.”

The department has confirmed infections of a Baskin-Robbins ice cream store employee and a Taco Bell worker, both at Oahu locations, since the outbreak began in mid-June. Health officials stressed that the businesses were not sources of the outbreak.

The long incubation period of the disease complicates efforts to find the outbreak’s source, Park said.

When symptoms emerge, they can show up two to six weeks after exposure — making it difficult for people to remember what they ate and where after so much time has passed.

The U.S. Centers for Disease Control and Prevention said last week officials were unaware of any other U.S. hepatitis A outbreak or cases that might be linked to Hawaii’s outbreak.

The state health department said officials have heard reports of some Hawaii restaurants offering the vaccine to workers.

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