Wilderness Medicine Podcast · Wilderness Medical Society

#34: Norovirus!

·58 min·3 clips

Norovirus particles can spread at least 25 feet after vomiting.

Dr. Daryl and Dr. Fred open the June 2024 show on one article. It follows an acute gastroenteritis outbreak among Colorado River participants in Grand Canyon National Park. The hosts make clear that norovirus can reach the backcountry too. They bring in a panel tied to the article and keep the discussion moving across medicine, epidemiology, and river logistics. The article lists Sean Amico, Laura Calderwood, Ariella Dale, Ronan King, Matthew Maurer, Maria Saeed, Lori Dyer, Sarah Mirza, and others among its authors. The investigation starts with illness reports and then moves into stool testing and groover testing, the portable toilets used on the river. Those tests point toward norovirus as the likely main cause. The team also considers possible transmission from wastewater, drinking water, and contaminated food from distributors. That search does not yield a clean answer right away. So Coconino County and park services request a CDC epi-aid. The show explains that an epi-aid is short-term technical support from EIS officers, those disease detectives, and other CDC subject matter experts. Local partners, outfitters, and guides then work with the CDC team on practical control measures. The outfitters already file GI illness case report forms when someone gets sick. That gives investigators a lot of useful detail to start with. The team also builds an online survey for river rafters and hikers. The survey asks about symptoms, meals, drinking water sources, treatment methods, and environmental exposures. The outfitters email the link to passengers on commercial rafting trips, widening the reach beyond the first reports. The discussion keeps turning the evidence into backcountry decisions. Filtration comes up with a pore size under one micrometer for most bacteria and parasites, chemical impregnation for resistant bacteria and tiny viruses, and charcoal mostly for taste. Reverse osmosis and distillation close things out, along with a practical note that reverse osmosis can help with metals, pesticides, and salts, and the show ends by noting CME credit for WMS members who finish the Journal Club questions.

As heard by us

A Grand Canyon norovirus outbreak becomes a grounded look at field epidemiology and remote outbreak response.

The June 2024 Wilderness Medicine Podcast follows a Grand Canyon norovirus outbreak and the public-health work behind it. It moves through the 2022 acute gastroenteritis outbreak among Colorado River rafters and backpackers, touching on groovers and wastewater, drinking water,…

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You want a backcountry outbreak story with groovers and CDC epi-aid help.

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