NAMPA -- Norovirus has been confirmed as the illness that kept hundreds of students out of class at Lone Star Middle School earlier this month.
Southwest District Health confirmed Wednesday that two stool samples sent to the lab had tested positive for norovirus.
About 180 children stayed home sick or were sent home after reporting illness May 7. The number of students out of class jumped to 468 - nearly 60 percent of the student body - the next day, due in part to the parents of healthy children keeping them home to avoid catching the virus.
Attendance at Lone Star Middle has returned to normal.
Southwest District Health spokeswoman Laurie Boston said the district could not determine how the outbreak started.
"Norovirus is very infectious and it lives a long time, especially on surfaces, so there's no way we could determine the source," she said.
Nampa School District spokeswoman Allison Westfall said the the school kitchens were inspected, and were found not to be contaminated. School officials will continue to disinfect Lone Star Middle through the end of the school year as a precaution.
