Guests at the hotel started falling ill Saturday afternoon. Most of them were members of Norway's diabetes foundation, which was holding a conference and 60th anniversary celebration at the hotel.
By Tuesday, however, more than 20 hotel employees and at least 10 other guests not tied to the diabetes group had reported getting sick. Even the band hired in to entertain at the foundation's anniversary got sick.
Officials initially suspected that something served at a lunch buffet set up for the diabetes group was the source of the food poisoning. Now they're not sure, given all the other cases of illness.
The hotel was shut down late Monday, initially for two days. It can take several more weeks, however, before authorities can determine the source of the illnesses.
