CHICAGO (WLS) -- More than 90 students who attended Victor J. Andrew High School's prom at Shedd Aquarium last week became sick with flu-like symptoms over the weekend, school officials said Monday.About 500 students attended the Tinley Park high school's prom, which was held Friday night."I was vomiting, I had diarrhea, I had a fever, I had everything," said student Kacie Johnston, who was too sick to leave her house on Monday.In a letter to families, Consolidated High School District 230 officials said they did not know the cause of the illnesses, and asked parents for information about their child's illness to help assist in identifying a source.Some of the students have reported being diagnosed with norovirus, a highly contagious infection commonly spread through food or water that has been contaminated during preparation.While not all the sick students have had the virus confirmed, enough of them have to make parents believe they're all suffering from the same thing."I was messaging with a few parents last night from immediate care," says Edith Paez, whose daughter Elizabeth is among those who are sick. "Some of them were in the hospital. Some of them were at the actual immediate care where we were."In a statement, Shedd said they are working with Sodexo, which caters Shedd's events, and the school to investigate."The care and well-being of all our guests is a top priority for Shedd Aquarium and something that is taken very seriously," said Andrea Rodgers, Shedd's vice president of communications and public relations. "Sodexo at Shedd Aquarium has a longstanding, strong performance in food safety and commitment to maintain strict adherence to food safety procedures that lead to clean, safe operations and nutritious food. We welcome and regularly participate in health inspections."A Sodexo spokesperson, said in a statement Monday afternoon: "The safety, health and wellbeing of our clients and customers is our top priority. We are aware of the alleged food-related illness at the Shedd Aquarium, which has affected students from Victor J. Andrew High School. We are conducting a thorough internal investigation in close partnership with the Shedd team and the local health officials. We are committed to food safety and have enjoyed a longstanding and strong performance of food safety procedures and operations at Shedd Aquarium."Monday morning, some parents rushed to Wisconsin Dells, where a group of about 40 students had gone to spend the weekend following prom. About half of them got sick; some so severely they had to take themselves to the hospital rather than wait for their parents to arrive."He was very scared. He had a hard time breathing," said Marci Condon, whose son Jack, is among the ill. "He's still very sick today. He hasn't gotten out of his room today. He has a fever, the chills. He's sweating."The city and county health departments are investigating, and the Illinois Department of Public Health said they are aware of the situation.The Cook County Department of Public Health said they plan to administer a questionnaire to students on Tuesday regarding where they were in the days leading up to prom.School officials, who are working with Shedd, want to know what food their child consumed, other activities they participated in during prom weekend and when the child first became symptomatic.Parents are asked to call the school's dean at 708-342-5894 to share information about their child's flu-like symptoms. Earlier Monday, school officials believed that 50 students were affected, but later increased that number to 90.The Andrew High School building will be cleaned overnight "in the event that a virus may have been introduced into the school as a result," Nolting said in a message to parents."It is saddening to see the excitement of an otherwise positive and memorable event dampened by this situation," Nolting said.