The norovirus outbreak that hit about 20 people at the Bancroft Convalescent Hospital in San Leandro on Jan. 20 still has the facility under quarantine.

The owner of the convalescent hospital said Wednesday that another nurse, who was on duty Tuesday, now has the bug. He also said a patient whose roommate already came down with it has symptoms as well.

Lea Brooks, a spokeswoman for the state Department of Health Services, said this is an unusual season for the norovirus. The department has seen a rapid acceleration of the disease since October, several months earlier than expected.

The department recently issued guidelines for managing the outbreaks at nursing homes and the like, which can be viewed here.

The outbreak at the convalescent hospital is still being monitored. The good news, the owner said, is that it could have been a lot worse.