Grand Canyon norovirus


Apr 1, 2021
Was anyone else contacted by the park to fill out a questionnaire about your recent trip there? Or did any of you get sick?

Apparently, over 100 norovirus cases have been reported from backcountry visitors since May, and it's even making the news. I saw an online post from a woman who used her Garmin to call in helicopter rescue for two hikers who couldn't stop vomiting and couldn't keep hiking out. A 41-yr-old woman became unresponsive and died last week, but no cause was given so it might've been heat only, or heat plus norovirus. Currently, the park says all water sources should be boiled or chemically treated (indefinitely), but I sure hope that's just a temporary thing.

I only dipped into the park for two nights from the Kanab Creek Wilderness, but they wanted to know a million questions about my personal hygiene and water treatment and sources. The last day while hiking out, I actually had stomach cramps for the first time on a trip. I assumed it was from temps in the 90's and the previous night's meal not being fully rehydrated (crunchy beans!). Now I'm not sure. Half of my water came gushing from a crack in the rock and was collected before even hitting the ground, and the other half was from Kanab Creek and hadn't been above ground for more than a few miles at most. I felt fine once I reached the car and removed the tight hip belt, but who knows...

I just assumed it only affected dirty rafters, but it seems to be affecting hikers, too. Could norovirus even get into groundwater and springs? Does it usually only affect the Colorado and come from human or animal feces?

The above site mentions several times Norovirus hit the canyon (river runners) and that it was thought to be caused by a faulty treatment plant inside Glen Canyon Dam. Even if this were true, it doesn't seem likely to affect hikers, unless it somehow was in the water table and thereby streams and springs, but the geology there is complex enough that this seems like a long shot. Kind of interesting, though.
it was thought to be caused by a faulty treatment plant inside Glen Canyon Dam.
Interesting. It seems like that would be an easy thing to check at the dam instead of investigating via questionnaires. I read it only takes 10 virus particles to make you sick, so with such tiny numbers I suppose even just one dirty rafter or one pile of backpacker poop washed into the river by rain might be enough to make people sick downstream.

I assume the recently affected hikers used a Sawyer while drinking water from the Colorado. This was my first trip in which I didn't drink from the Colorado. It's a scary place to have that type of illness as a hiker, but nobody likes to use chemicals or heat to treat water. I hope the NPS publishes their findings, though the investigation might not be concluded for months.
That link I posted was quite old. I have no idea if they checked into the water plant or not but you would think they had. I just posted it to show that this seems to be a recurring problem.
So it seems to happen every 5-10 years on the Colorado in Grand Canyon, and mostly with rafting groups. Has anyone heard of this problem in backpacking areas other than the Grand Canyon?
I don't ever drink untreated...years ago did, but now there are too many people and animals wandering around that don't care of hygiene. Even what looks like a spring may not be safe, may have groundwater getting into it close to where it flows out I use the full range ... Filter mostly, but have. And carry aquamira, in the GC, little Colorado specifically we boiled, found it precipitated the minerals out and made the water better..
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