The Associated Press

PUT-IN-BAY - Health officials said Sunday that more than 100 additional cases of a gastrointestinal illness have been confirmed among visitors to this resort area.

Researchers have identified 630 cases, up from 510 Saturday, said Jay Carey, a spokesman for the Ohio Department of Health. Interviews still need to be done with 192 people who have reported symptoms, he said.

Most people have said they suffered from cramps, diarrhea, nausea, fever and chills within two or three days of visiting Lake Erie's South Bass Island.

Carey said tests have confirmed cases of salmonella, norovirus and campylobacter among the victims, who've reported symptoms lasting from a day up to a week.

Most of the people became ill within the past three weeks, including as recently as Friday, but some cases date to June, Carey said Sunday.

No cause has been found and nothing has been ruled out, he said.

"What we're looking for now is other commonalities their visits may have had," he said.

Despite the illness, there are no visitor restrictions in the area, Carey said.