WALNUT CREEK -- A local steak house has been given the go-ahead to reopen after diners and employees contracted norovirus last week, county officials announced Friday.

Fleming's Prime Steak House and Wine Bar, located at 1685 Mt. Diablo Boulevard, was closed Wednesday after county health officials received two separate complaints of patrons falling sick after dining at the restaurant last week, said Erika Jenssen, Contra Costa Public Heath communicable disease programs chief.

Representatives from the restaurant were not immediately available for comment.

Jenssen said Fleming's was allowed to reopen for service Friday evening after the restaurant received a thorough cleaning and employees attended a food safety class.

It is unknown just how the diners contracted the virus, which causes severe nausea, vomiting and a low-grade fever, among other symptoms.

At least one employee also tested positive for the virus, while other employees displayed norovirus symptoms but did not test positive, Jenssen said.

In January, North Park Deli in Concord was closed because of norovirus, and a school in Lafayette also had several students fall ill after an outbreak was reported.

Outbreaks of norovirus are not infrequent or unexpected this time of the year, according to Corey Egel, spokesman for the California Department of Public Health.

The strain being reported in the Bay Area, as well as across the United States, is a new strain, Egel said, leaving people more susceptible to picking it up. New norovirus strains generally appear every few years.

The Centers for Disease Control and Prevention recommends that people wash their hands frequently, particularly after using the restroom, changing diapers, having any contact with vomit or feces and before food preparation.

Those who are sick should avoid preparing food and stay home from school or work until the symptoms have subsided.

Check back for updates.

Contact Katie Nelson at 925-945-4780 or follow her at Twitter.com/katienelson210.