Delaware health officials have determined the cause of gastrointestinal illness that spread among members of the Olentangy Orange High School marching band during a trip in Atlanta.

Three lab results have come out positive for norovirus, said Travis Irvan, program manager for disease prevention from the Delaware General Health District.

“This is the typical time of the year” for the virus, Irvan said.

Norovirus causes inflammation of the stomach and/or intestines with common symptoms including diarrhea, vomiting, nausea and stomach pain, according to the Centers for Disease Control and Prevention.

The district recommends people to wash hands and stay home if they are sick, Irvan said.

About 250 students from the marching band participated in the 2016 Chick-fill-A Peach Bowl on Dec. 31 in Atlanta. Band performers were at the College Football Hall of Fame, Chick-fil-A headquarters and a competition during the trip.

Additional appearances included the Peach Bowl Parade and the Mass Band Show at the Peach Bowl Fan Experience on New Year’s Eve. The OOHS Jazz Band and Wind Ensemble participated in adjudicated events and a clinic administered by professors from the University of Illinois, Ohio University and the University of Georgia.

Irvan said the health district is working with the school as part of its investigation and would not release how many students were ill.

School officials had extra cleaning performed throughout the district’s facilities per the recommendation of the health district and school nurses, said district spokesman Devon Immelt.