LEILA FADEL, HOST:
Hundreds of visitors to the Grand Canyon took home more than selfies and prickly pear candy this summer. A record number of norovirus cases hit the park's backcountry. There were so many cases the National Park Service asked for help from the Centers for Disease Control and Prevention. Luke Runyon of member station KUNC spoke with some of the unlucky travelers.
LUKE RUNYON, BYLINE: Jacquie King and a group of 14 friends launched their rafts into the Colorado River in early May. The trip started smoothly, other than it being unseasonably warm. But when they ran into other rafters, they were warned. Norovirus was sweeping through the canyon. By Day 9, one person in King's group was sick - stomach troubles.
JACQUIE KING: After patient zero, it was one to two people a day going down. Our worst day was when we ran Upset Rapid.
RUNYON: Upset is a huge, roiling whitewater rapid right in the middle of the canyon.
KING: And we had three people go down almost instantly after we got through the rapid - people vomiting over the side of the boat, just couldn't hold anything in.
RUNYON: King became ill that same day. Her group had a military-grade metal rocket box to use as a toilet. That's required of all rafters to store human waste from the three-week-long trip. And theirs was getting a lot of use.
KING: You're sitting on a rocket box in the outdoors in the middle of nowhere, hugging a bucket. And it's - I mean, it's about as uncomfortable as you can imagine.
RUNYON: King's group wasn't alone in its misery. Justus Burkit and his wife backpacked the canyon two weeks after King floated through.
JUSTUS BURKIT: I would say about two hours after I started drinking the water from the river my stomach was in tremendous pain. Like, it felt like there was, like, a balloon being blown up from inside of me that was, like, being overfilled.
RUNYON: Both King and Burkit were part of what a new CDC report calls the largest documented outbreak of norovirus in the Grand Canyon backcountry. From April to June of this year, there were more than 200 confirmed cases and likely a lot more that went uncounted. Sharon Hester is with Arizona Raft Adventures, which outfits trips in the canyon. She says a few of their guides got sick this spring. And it can be tough to keep germs from spreading even in the great outdoors.
SHARON HESTER: What they do is try to put them in a boat where they're the only one rowing or they're the only person in that boat. Or if there's, you know, someone else sick, it would be the sick boat where everybody would try to stay away.
RUNYON: Hester says norovirus has been a problem in the canyon for years. The virus can live in the river's tepid water and then easily spread among groups who all use the same toilets and eat communally. The CDC report says the virus can even survive in beach sand, where rafters set up camps, allowing it to spread between trips. As the number of tourists visiting the national park has grown and outbreaks have become more frequent over the years, Hester says raft companies have been forced to change protocols.
HESTER: Don't vomit in the river. Vomit in a garbage bag. You know, isolate people, handwashing. You know, it got more and more strict, making sure the water was always purified.
RUNYON: By the time Jacquie King's group of 15 people got off the river, all but four in her group had come down with norovirus. Even with all of this stomach trouble, would it keep her away from another Grand Canyon trip?
KING: Oh, no, no. I, like - I am chomping at the bit to go back down and have a different experience.
RUNYON: A trip where no one has to hug a bucket.
For NPR News, I'm Luke Runyon in Grand Junction, Colo.
(SOUNDBITE OF BILLY STRINGS SONG, "HIDE AND SEEK") Transcript provided by NPR, Copyright NPR.