Officials not sure what caused 50 hotel guests to fall ill MADISON, Wis. (AP) -- Madison health officials are still investigating why dozens of visitors fell sick this weekend while attending a science-fiction convention. Officials with Dane County and the Madison Public Health Department say the illness that struck about 50 people still hasn't been identified. Investigators say the ailment had symptoms similar to those of stomach flu. They think some attendees might have been exposed to the illness before the convention since they developed symptoms so soon after arriving. The sick ones may have then infected others through personal contact and shared access to food. The convention was at Madison's Concourse Hotel. General manager Steve Zanoni says the hotel has been thoroughly scrubbed since the illnesses were reported. --- Information from: WISC-TV, http://www.channel3000.com © 2008 The Associated Press.