More than 30 Marines at a Southern California base are being confined to quarters after one tested positive for swine flu Wednesday.
The Pentagon confirmed Wednesday that the Marine at the Twentynine Palms Base has the swine flu and is under quarantine, along with his roommate.
A Marine spokesman at the Pentagon, Maj. David Nevers, said the sick Marine is doing well and his condition continues to improve.
Nevers said approximately 30 others who had been in contact with the sick Marine at the Twentynine Palms base will be held in quarantine for five days as well as to see whether they show symptoms.
At the end of the five day period, if they display no flu-like symptoms they will be returned to full duty, according to a release from the base.
Meanwhile swine flu fears have led authorities to close a Northern California high school, while San Diego State University officials were investigating a student's illness.
Barracks and schools are breeding grounds for disease transmission because many people are in close quarters.
San Jose's Branham High School will be closed for a week because an unidentified student was suspected of having swine flu. The 16-year-old girl was last in school Thursday. Santa Clara County officials said her sample and 23 others were being tested.
San Diego State University officials announced late Tuesday that one of their students has a suspected case of swine flu, and was receiving treatment after experiencing fever, respiratory illness and testing positive for type A influenza. The student's condition is not considered life-threatening. The school planned a press briefing Wednesday.
Education officials urged parents of the state's 6.3 million students to keep sick kids at home but keep sending healthy children to classes.
Arthur Reingold, the head of the Division of Epidemiology at the University of California, Berkeley, said children are a common conduit for disease so schools are a good place to focus.
"In influenza viruses of any kind, much of the transmission in the community happens among school-age children," he said.
The problem lies in students, especially very young ones, who lack hygiene skills such as keeping coughs and sneezes to themselves, said Dr. Bonnie Sorensen, chief deputy director of the California Department of Public Health.
"Our schools are the germinators," she said.
State health officials said that as of Tuesday night there were 11 confirmed swine flu cases in California. Individual counties have reported other cases that have yet to be confirmed by the state.
Los Angeles County, the nation's most populous with more than 10 million people, had no confirmed cases as of Wednesday morning, said Dr. Jonathan Fielding, the county director of public health.
So far only a handful of public and private schools have closed in California because of confirmed swine flu cases or investigations into illnesses.
Teachers at Highlands Elementary School in Pittsburg contacted parents Tuesday night to tell them the school will be closed for a week after tests from Contra Costa County health officials revealed three probable cases among fourth-graders, Superintendent Barbara Wilson said. The cases had yet to be confirmed by the state.
School authorities, meanwhile, say parents shouldn't keep healthy children home.
"Our schools are safe. We want students to continue to come to school," said Jack O'Connell, state superintendent of public instruction.
San Diego and Imperial counties have five state-confirmed cases each of swine flu.
A private Lutheran elementary school in San Diego, Christ the Cornerstone Academy, was closed Tuesday after a 7-year-old boy was confirmed as having swine flu, said Jose A. Alvarez, a spokesman for the San Diego County Health & Human Services Agency.
It was not immediately clear how the boy contracted the illness. The boy's father and sibling also are suspected of having the flu, said Alvarez.
State officials confirmed one swine flu case in Northern California involving a Sacramento County student. Officials in Sacramento and Marin counties each reported two additional cases, and Santa Clara and Tulare counties each reported one.
Sacramento County health officials said a teenage student at St. Mel School in Fair Oaks who traveled to Mexico did not test positive for swine flu, but three other students did, including the one case confirmed by the state. The school will be closed for the rest of the week.
In Marin County, officials said a 60-year-old woman and her 20-month-old granddaughter tested positive for swine flu after a Mexico vacation that took them to Cancun, Cozumel and Playa del Carmen. They were not hospitalized but were staying home.