E. coli bacteria was found in water at a popular zip lining attraction in Tennessee where more than 500 people reportedly fell ill, health officials said.

The state’s health department said last week one person who visited the CLIMB Works Zipline Canopy Tour in Gatlinburg tested positive for norovirus and enteropathogenic E. coli, while at least another 550 people tested positive for norovirus.

“At this time we cannot point to one simple cause of this outbreak,” said TDH Deputy State Epidemiologist John Dunn, DVM, PhD, in a statement.

WHAT IS BACTERIAL MENINGITIS? SIGNS, SYMPTOMS AND TREATMENT FOR THE INFECTION

Norovirus causes acute gastrointestinal illness and is often characterized by sudden onset of nausea, vomiting and diarrhea; symptoms typically last one to two days. Enteropathogenic E. coli causes watery diarrhea; symptoms may last several days.

“Preliminary testing and environmental health assessments indicate the water system at the zipline facility may have contributed to the outbreak; however, there are likely other sources involved in the spread of the illnesses, including contaminated surfaces and person-to-person transmission,” Dunn said

He said water testing indicated that there was fecal contamination of the facility’s water system and that additional testing was underway.

“It’s important to note that while norovirus is reliably identified in stool samples during outbreak investigations, identifying it in food, water and the environment is more challenging,” Dunn added.

INFANT DIES DAY AFTER SHOWING SYMPTOMS OF MENINGITIS, FAMILY SAYS

Since June, multiple visitors to the facility have complained of falling ill, with one person, Emily Oney, posting on Facebook that her experience was a “terrible way to end our family vacation.”

“The tour itself was fine. We had a group of 8 for the mountaintop tour on Saturday morning. By Sunday afternoon, 6/8 (including a 9 and 11 year old) of us were throwing up and terribly sick and could not figure out why,” she wrote in a post. “Do not drink the water here. Climb Works should make this right with all the families that were affected by this. Terrible way to end our family vacation.”

Gail Harmon, East Tennessee regional assistant director with the Tennessee Department of Health, told WVLT that nearly 2,901 people who booked zip line tours with the company received surveys. At least 550 of those who responded reported illness.

CLIMB Works owner Nick Thompson told WTVR that they “feel awful for anyone that got sick.”

“We have implemented every recommendation from the Health Department and are currently only using complimentary bottled water for our drinking water and added an additional chlorination system for our non-potable water,” he said in an email. “We feel awful for anyone that got sick and are asking anyone affected to contact us directly so we can help make the situation right for our guests.”