A likely outbreak of what's commonly called stomach flu caused about 40 students staying at George Mason University to become sick this week.

The Fairfax County Health Department said Thursday that it was investigating an outbreak of viral gastroenteritis among students participating in a program sponsored by the Congressional Award Foundation.

About 40 of the 80 students became ill. Physician Peter Troell (TROLL) with the county health department said the students likely contracted the virus that can cause vomiting and diarrhea. The disease is often referred to as "stomach flu" even though it is not caused by influenza viruses.

Germs like norovirus and rotavirus can sometimes be responsible for outbreaks of gastroenteritis.

Troell said health officials are testing to see if a specific virus is responsible.