The Ohio State Health Department has determined drinking water contaminated by sewage and other pollution was most likely the reason why 1,400 people fell ill last summer on a Lake Erie resort island.
After visiting South Bass Island, which is about halfway between Toledo and Cleveland, tourists and residents suffered symptoms of fever, diarrhea and vomiting.
The department found that the island's wells were tainted when porous soil allowed sewage from septic systems and runoff containing bird droppings and lawn fertilizer to infiltrate groundwater, the department said.
Most vacation homes and businesses catering to tourists draw their drinking water from the municipal system which tested negative for contamination after the outbreak about 400 draw water from wells.
However, in tests of private wells, investigators found that eight of 10 contained bacteria, including E. coli in some cases, the report said.
Officials have expedited a $5.2 million project to expand the municipal system to all island businesses. It is scheduled to be finished in about two years.