El Paso County health officials are investigating reports of an intestinal illness that appears to have sickened a large number of students of Falcon Middle School.

Falcon School District 49 officials reported the illnesses Thursday afternoon to the El Paso County Department of Public Health after an unusually high number of students either called in sick or complained of vomiting or diarrhea, said Dr. Bernadette Albanese, medical director of the department.

Though it’s unknown exactly how many students became ill, the number could be more than 100, she said. The school’s 2010 enrollment was about 900, according to the Colorado Department of Education.

While outbreaks of illnesses in schools or other institutions aren’t uncommon, she said it was unusual for such a large number of students to be ill on a single day.

Health officials are investigating whether the illness is due to something the students ate or whether it spread from person to person. The investigation could take several days, she said.

Albanese asked parents keep any sick children home in case the intestinal illness is contagious.

“The last thing we want to do is to have people who may have a contagious illness give it to another person,” Albanese said.