Norovirus: Yellowstone National Park Outbreak

Those heading on a camping trip this summer might want to be just as wary of crossing paths with the wrong bacteria as they would a hungry bear.

After 200 park employees and visitors reported bouts of gastrointestinal illness at Yellowstone National Park and nearby Grand Teton National Park this month, national park officials have warned visitors to be vigilant about hygiene.

The outbreak started on June 7, when a group touring the Mammoth Hot Springs complained of stomach flu and other gastrointestinal problems. After the tour group members reported their illnesses, about other 50 visitors and 150 park employees reported similar symptoms.

Preliminary reports found that they had norovirus, or “stomach flu,” which affects up to 21 million people, every year according to the Centers for Disease Control and Prevention.