One employee at Cafe Pinot, located next to the Central Library, has hepatitis A, and three other employees have symptoms that are consistent with the disease, health officials said.
Representatives from Cafe Pinot had no immediate comment.
Health officials said they have not found a reason to close the restaurant, but that anyone who may have eaten at Cafe Pinot since Thanksgiving should immediately contact their physician to receive immune globulin to prevent possible disease, health officials said.
"The source of the illness among the four employees is unclear at this time," said Dr. Jonathan Fielding, director of public health. "We will continue our investigation to assure the public is safe from exposure to the disease."
Patrons should receive immune globulin as soon as possible, but no later than two weeks after possible exposure, officials said.
This weekend, the health department will provide immune globulin to patrons who may not be able to receive it from their physicians. The Central Health Clinic, at 241 N. Figueroa St., will be open from 9 a.m. to 1 p.m. Saturday and Sunday.
Hepatitis A is usually spread from person to person through a fecal-oral route. Thoroughly washing hands with soap and hot water after using the bathroom and before handling food can help prevent the spread of the disease.
Symptoms of the disease include fever, chills, muscle aches, fatigue, jaundice, nausea, loss of appetite and vomiting.
The number of reported hepatitis A cases in Los Angeles County is up this year.
Thirteen diners at anot4Y.MQUI9Qwere infected with hepatitis A in September. One month later, 19 people were infected after eating contaminated lettuce at a catered event, health officials said.
In October, there were 32 reported cases of hepatitis A in Los Angeles County, compared to five in October 2004.
Unwashed produce also can transmit e. coli and salmonella.
"All produce -- even those that come pre-packaged and labeled as having been washed -- should be rinsed in cold running water," Fielding said.
For questions about hepatitis A, the public can call the county Department of Health at 1-800-427-8700.