While hiking in Grand Canyon National Park, Kristi Key came across a disturbing site: four hikers resting on the side of the trail look a little worse for wear. After learning that two of the hikers had vomited violently the previous night, Key offered to call a rescue team, but the group declined. But when she saw them sitting in the same spot on her return journey, with one of the hikers still vomiting, she knew it was time to call for help.
Finally, a helicopter appeared and carried the sickening man to safety. But the experience stuck with Key, who told The Daily Beast that she’s hiked hundreds of miles in the Grand Canyon and, until now, never encountered hikers whose illness had nothing to do with dehydration or heat. After a once healthy member of the unlucky group fell ill later that day, Key began to suspect a virus was the cause.
As of June 10, the park had known 118 people who had fallen ill with a gastrointestinal virus, Grand Canyon News reported. The infections spanned 16 different trips up the Colorado River and in the backcountry.
A majority of the diseases were registered in May, the most recent case was reported on June 2. According to Jan Balsom, chief of communications, partnerships and external affairs at the Chief Inspector’s Office at Grand Canyon National Park, the park has been issuing warnings about the gastrointestinal virus since May 20. †
“We haven’t seen anything like this type of outbreak in about 10 years,” Balsom said. In fact, Balsom herself had a run-in with what she called the “unusual” increase in gastrointestinal distress when a woman on a river trip she recently attended contracted a stomach virus less than 12 hours into the trip. However, the woman does not know whether she was infected with the norovirus or another disease, a predicament that illustrates many of the difficulties in investigating the outbreak.
There is a limited amount of time in which one can collect stool samples to confirm a norovirus infection, Balsom said. River trips typically last longer than that critical period, meaning it’s often impossible to accurately diagnose a person’s illness.
The park is questioning visitors to make sure their water isn’t just filtered, as norovirus isn’t killed by point-of-use filters. It must either be chemically disinfected or boiled. It also asks that visitors not drink from waterfalls, pools, or streams.
†[Officials] have followed up the interviews of participants on trips who have become ill,” said Balsom. “They tested poo scans to determine if it’s noro or not.”
In a statement to The Daily Beast, a National Park Service Office of Public Health official described the outbreak as an “exacerbated GI illness” and said an investigation “will consider all possible sources. It is currently unknown what causes the disease.”
Individuals have taken to social media to share their stories of journeys cut short by vomit, and posted long sagas of walks gone horribly wrong.
One man wrote that he was overcome by vomiting in the middle of the night, with his nausea lasting from 1 a.m. to 5 a.m.
“Let me tell you,” he wrote, “being sick and weak and walking 1200 feet in elevation in 2.5 miles is not a move.”
In another message in may in the “Grand Canyon Hikers” Facebook group, a woman notified others of the norovirus outbreak, describing that she became ill just after she left the canyon.
“I wouldn’t have been able to walk out or fend for myself if I had started throwing up in the canyon,” she wrote. “GC public health officials are closely monitoring the situation. Apparently it’s a big one.”