The Washtenaw County Health Department is investigating after dozens of women at the University of Michigan chapter of the Delta Delta Delta sorority became violently ill after eating together on Friday.

Health Department epidemiologist Laura Bauman said the symptoms are consistent with norovirus, which is among the numerous culprits for food poisoning. Until the investigation is complete in a few days, the department can’t be sure that’s what it is, she said.

The Ann Arbor police and fire departments went to the sorority house at 718 Tappan Ave. at 10 p.m. Saturday after a caller said 37 women were ill. An Ann Arbor Fire Department press release reported that women at that address and in the 800 block of Hill Street were also vomiting and not feeling well.

Ann Arbor police and fire departments responded Friday to the University of Michigan chapter of the Delta Delta Delta sorority after several dozen women reportedly fell ill following a communal meal. The Washtenaw County Health Department is investigating the incident.

Juliana Keeping | AnnArbor.com

Friday, four fire trucks responded due to the number of patients, as well as Huron Valley Ambulance, which took three women to area hospitals, according to the release. Other women had gone to the hospital on their own earlier, though it wasn't clear how many, the release stated. The Fire Department checked for gases and found nothing that could account for that many ill people, the release said.

The Health Department will take food histories from those who got sick and sorority members who didn’t get sick to compare what they ate and try to isolate what food might have been the culprit.

Noroviruses are a group of viruses that cause gastroenteritis, an inflammation of the lining of the stomach and intestines, according to the Centers for Disease Control. Symptoms typically include nausea, stomach cramping, vomiting and diarrhea. Noroviruses are found in the vomit and stool of infected people and are very contagious. Symptoms appear 24 to 48 hours after ingestion of the virus through contaminated food or liquids, surfaces or objects or other contact with someone who is ill. Bauman said it will take three to four days to determine if noroviruses are the culprit. She said there are around six outbreaks per year linked no noroviruses in Washtenaw County. An outbreak is more typically in the 10-to-20-person range, though norovirus outbreaks have sickened hundreds of local people at once.

In the mean time, the women are recovering and the house is being sanitized to prevent the spread of the illness, Jason Gomez, the director of chapter services for the group's executive office, said in an e-mail to AnnArbor.com. The women transported to the hospital were treated for dehydration and released the same evening, Gomez said.

Juliana Keeping is a health and environment reporter for AnnArbor.com. Reach her at julianakeeping@annarbor.com or 734-623-2528. Follow Juliana Keeping on Twitter