Shenandoah Valley Elementary School in Chesterfield will be closed Thursday due to an illness outbreak.

School officials say more 60 students were out sick Wednesday with some kind of stomach virus or flu. Many staff members were also sick this week.

"It just comes on so fast and it just spread... like wildfire," said Shenandoah Valley Principal Carrie Luttrell.

Luttrell said the Parkway School District consulted with the St. Louis County Health Department before deciding to cancel school Thursday. She said health officials are also testing cultures to determine what, exactly, the virus is. Symptoms include nausea, fever, vomiting, and diarrhea. 

Wednesday night, the district directed additional custodial staff to the elementary school to deep clean the building.

"We now have a team of five going into every room, cleaning every hard surface with a special cleaner to address the virus," Luttrell said. 

Spring break was starts Friday in the Parkway District, so students at Shenandoah will get an extra day now. 

Luttrell hopes a long week away from the building means healthy students and staff when they come back to class.

"We knew this was highly contagious and we just needed to really get the children home, and start our spring break, in order to clean and give them a safe environment when we get back."