By Emmett Berg
SAN FRANCISCO (Reuters) - A Jesuit high school in San Francisco was closed down for the rest of the week on Wednesday after about 300 students and 30 faculty were stricken by a stomach ailment marked by nausea and vomiting, officials there said.
The outbreak at Saint Ignatius College Preparatory school, initially believed to have been caused by a virus, sent a handful of the sickened students to hospital emergency rooms for treatment of dehydration, principal Patrick Ruff said.
He said he did not know if any were admitted.
"A large percentage of students and about 30 faculty are sick, and we thought it would be best to close on Thursday and Friday," Ruff told Reuters, adding that about 50 students called in sick on Wednesday and more than 100 left during day.
But school spokesman Paul Totah said roughly 300 pupils in all, out of the school's 1,360-member student body, were believed to have been affected in some way.
Extra maintenance staff were brought in to scour the entire school with a bleach-based solution, and the process will be repeated on Thursday, Ruff said.
The school consulted with San Francisco health inspectors, who visited the school Wednesday and ruled out cafeteria food or waterborne sources as the origin of the outbreak, he said.
For now health officials were describing the malady generally as viral gastroenteritis, often called stomach flu even though the illness is not related to influenza, Ruff said. But further testing is needed to determine whether norovirus, a common cause of gastroenteritis, was the culprit, he said.
In a message to parents updated Wednesday afternoon on the school's website, officials said students should stay home at least 72 hours after symptoms have subsided, and added that "athletes who experience symptoms should not attend practices or competitions."
In what may have been an early sign of the outbreak, members of the Saint Ignatius girls' varsity basketball team suddenly fell ill with a bout of vomiting during the third quarter of a game against another school, Sacred Heart Cathedral, Totah said.
One of the girls was a player who had just "had the game of her life," hitting five three-point shots and 20 points overall before and her teammates were stricken, he said, adding that all reported feeling healthy before the game.
The school's gymnasium was inspected Wednesday and was not considered an infected area, Ruff said. Freshman and junior varsity games against Sacred Heart went off without incident, he said. "It's so fast-acting that had it been we would have known about it quick," he said.
(Editing by Steve Gorman and Greg McCune)