Levels of a pathogen than can destroy brain cells and lead to death have been found in thermal features in Grand Teton National Park and the adjacent John D. Rockefeller Memorial Parkway in Wyoming, leading park officials to urge visitors to avoid Huckleberry Hot Springs, Polecat Springs, and Kelly Warm Spring.

Recent water testing indicates elevated levels of Escherichia coli (E. coli) and presence of Naegleria fowleri (N. fowleri) in the geothermal features, and nearby pools and streams, a park release said. According to the Centers for Disease Control and Prevention, the fatality rate for individuals infected by Naegleria fowleri is 97 percent.

“Due to increased evidence of harmful pathogens we highly encourage individuals to avoid contact with these waters,” Grand Teton Superintendent David Vela said. “It is our responsibility to protect these geothermal resources within the park and parkway, provide for a safe experience for our visitors, and communicate our scientific findings, especially as it relates to the health and safety of our visitors. “

The National Park Service is working in partnership with U.S. Geological Survey and Center for Disease Control and Prevention to conduct water-quality assessments and pathogen sampling in geothermally influenced waters within the park and parkway.

Escherichia coli is bacteria that normally lives in the intestines of people and animals. Some Escherichia coli bacteria are pathogenic, causing illness such as diarrhea, urinary tract infections, and respiratory illness.

Naegleria fowleri is a natural single-celled organism commonly found in warm freshwater. Infection with Naegleria fowleri is rare, and the infection risk is low. But, infection is likely fatal, the park said.  This pathogen infects people when water containing the organism enters the body through the nose. The organism then travels up the nose to the brain where it destroys brain tissue, causing swelling and ultimately death.

Public entry into geothermal features is prohibited within the parkway, including Huckleberry Hot Springs and Polecat Springs, and discouraged throughout the park, including Kelly Warm Spring. Access to nearby overflow or runoff pools or streams not solely of thermal origin are available for public use, but caution should be used. Alteration or disturbance of any water course from its natural state by damming, diverting or digging is not allowed.

“These fragile geothermal areas are significant and popular features of the Greater Yellowstone Ecosystem, and need to be protected and managed with care and good science," said Superintendent Vela. "Additional monitoring and testing of these areas will continue in the park and parkway.”