photo of a classroom with unoccupied desks and chairsLast Friday in Lafayette, California, Burton Valley Elementary School had an absence rate more than four times the normal one.  Over 100 students were out of school, many of them experiencing nausea, vomiting, and diarrhea.  The most likely culprit? Once again, norovirus. A nearby middle school also experienced a higher than normal absence rate, possibly including siblings of the sick elementary school children. The county has experienced about a dozen norovirus outbreaks in recent weeks. The school system is taking measures to scrub down and sanitize surfaces, and has asked parents to keep sick children home from school for at least 48 hours after illness. Many of the students had recovered by mid-week.

Details at KTVU.com.