Norovirus, not E. coli bacteria, caused the nausea, vomiting and diarrhea that afflicted between 30 and 50 people who visited Elk Lake Resort earlier this month.

The Oregon State Public Health Laboratory on Thursday announced that norovirus, a highly contagious infection that causes stomach pain and acute gastroenteritis, was found in the fecal samples of people who got sick at the resort.

Resort officials also found E. coli bacteria in the drinking water there, but officials say that wasn’t the cause of the outbreak.

Mitch Cole, a managing partner of the resort, said the well water was flushed and chlorinated to get rid of the E. coli.

“As soon as we got reports of illness, our first reaction was to bleach and disinfect everything,” he said. “We’ve probably done that six or seven or eight times over the last week and a half or two weeks.”

Cole said county health officials met with Elk Lake Resort officials Thursday morning and were pleased with the steps they’d taken to disinfect the resort.

“Unfortunately there’s nothing anyone in the hospitality industry can do (to prevent norovirus),” he said. “A guest can bring it in, and it’s just highly contagious.”

Tom Kuhn, the community health program manager at Deschutes County Health Services, said E. coli is found in well water but doesn’t always make people sick. The norovirus may have also been in the water, but health officials may never know the origin of the virus.

The most recent case was reported July 14. No one infected with the norovirus was hospitalized.

To be eligible to reopen, the resort had to get rid of anything potentially infected with the virus, like food or laundry. Employees sanitized all areas of the resort, including the restaurant, cabins and kitchen.

Well water samples taken earlier this week indicate the water no longer has E. coli in it.

“We’re doing one more water sample,” Kuhn said. “If that comes back negative, then I think we’re well on our way for the resort to be on track.”

While the resort remains under a “boil water” alert until further testing is completed, the resort and its restaurant are open to the public. The lake water was not affected by the illness, and the Cascade Lake Swim Series scheduled for next week in the lake will still take place there.

The resort, on the Cascade Lakes Highway west of Bend, is a popular destination each summer, with between 500 and 1,500 visitors on a busy weekend.

What is norovirus?

Norovirus is a highly contagious virus spread from person to person and via contaminated food, water and surfaces.

It causes diarrhea, stomach pain and vomiting, and usually lasts between one to two days.

There is no vaccine to prevent or drugs to treat norovirus illness.