Concerned about the rapid spread of swine flu, the state health department on Wednesday urged that schools be closed even when just one person has been confirmed to have the disease.

The California Department of Public Health said the action was necessary to prevent the rapid-fire spread of the virus, which has now sickened dozens of people nationwide. Health officials also said parents, staff and students should avoid congregating outside shuttered schools to prevent exposure.

Four public California campuses, including two in the Bay Area — Highlands Elementary in Pittsburg and Branham High in San Jose — already have been shut down due to outbreaks. Those schools — which serve a combined 2,045 students — will remain closed for seven days, the time period health officials recommend. A private school in Sacramento County, which had three students with confirmed cases of swine flu, has also been closed.

"I anticipate a number of school closures around the state as this moves on," Contra Costa County Health Services Director Dr. William Walker said Wednesday at a news conference in Pleasant Hill.

Contra Costa health officials confirmed that Marina Vista Elementary in Pittsburg also is being monitored after several children showed flu-like symptoms. Officials would not say if or when that school will be closed as well.

State schools chief Jack O'Connell this week urged parents to keep sick children home and encouraged thorough hand-washing. He also asked school districts to be ready to respond to possible local outbreaks through emergency response plans.

"It's critical that the 6.3 million students in California step up to make sure they remain free of this virus," O'Connell said.

There are no plans to close all state schools as a precautionary measure, O'Connell said, adding parents should not keep healthy children home from school.

"Our schools today are safe," O'Connell said.

The school closures come as districts are preparing for their annual state-mandated standardized tests. O'Connell said any closures won't affect the testing, because schools have a 21-day grace period in which to administer the tests.

Assemblyman Tom Torlakson, D-Antioch, plans to introduce a bill that would reimburse schools for state money lost during closure. Aside from the local public schools, elementary schools in San Bernardino and Tulare counties have been closed.

Schools are "suffering hard times already so this will assure that they don't lose average daily attendance money or any other funding that they would get otherwise," Torlakson said.

Panicked parents have bombarded local school district officials with questions about swine flu. Many Bay Area district leaders said they were on alert and checking student health and attendance closely. Most have sent letters to families urging precaution.

"I want you to know that we are in close contact with county health officials and are monitoring the situation very closely," Kirk Black, associate superintendent for the San Mateo Union High School District, said in a message to parents.

Albany school district officials said they plan to temporarily stop offering a salad bar with school lunch to prevent the spreading of germs. Other district officials remain concerned.

"We're in wait and see mode," said San Ramon Valley school district spokesman Terry Koehne.

Reporters Neil Gonzales, Eric Louie and Robert Jordan contributed to this story. Reach Kimberly S. Wetzel at 510-262-2798 or kwetzel@bayareanewsgroup.com.