More than 100 people reported getting sick after attending a conference at the Hilton Chicago hotel in July. Health officials say the kitchens at the hotel passed an inspection and hotel employees are cooperating with the ongoing investigation to identify the still, as yet, undetermined source. The department said there was no evidence of ongoing transmission of illness from the Hilton kitchens or anywhere else conventioneers may have eaten.
Usual symptoms of Norwalk virus infections include nausea, vomiting, diarrhea, and abdominal pain. Headache and low-grade fever may also accompany this disease. The disease is usually mild and brief. It will develop 24 to 48 hours after contaminated food or water is ingested and lasts for 24 to 60 hours. People infected with Norwalk Virus usually recover in 2 to 3 days without serious or long-term health effects.
A 1999 study suggests that Norwalk may cause more outbreaks of food-borne illness than all bacteria and parasites. It is estimated that nearly 65% of nonbacterial gastroenteritis in the United States is attributable to Norwalk and Norwalk-like viruses. Approximately 181,000 cases occur annually, with no known associated deaths.