The messy mystery of vomiting on the Pacific Crest Trail has been solved

Man holding stomach in discomfort while hiking
(Image credit: Getty)

Researchers have identified the source of an outbreak of vomiting and diarrhea on the Pacific Crest Trail (PCT) last year, tracing it back to a specific log cabin used for bathroom breaks.

Last summer dozens of hikers on the PCT began to feel unwell. Symptoms came on suddenly, including stomach pain, nausea and vomiting, and usually lasted a couple of days, cutting their adventures short. The diagnosis was norovirus, a particularly contagious illness that spreads easily on contaminated surfaces.

Outbreaks have been recorded on various popular hiking routes. Between April and June 2022, over 200 people were struck down by vomiting and diarrhea while hiking and rafting in the Grand Canyon.

It was the biggest outbreak of acute gastroenteritis ever recorded at the National Park, and led to a warning from the Centers for Disease Control and Prevention (CDC) urging people to practice better hygiene outdoors and clean up thoroughly if someone is ill.

Disease detectives

The CDC also carried out an investigation into last year's norovirus outbreak on the PCT, and has now announced its findings. In an interview with NPR, communicable disease expert Arran Hamlet explained that he surveyed hikers along a 70km stretch of trail, and identified a log cabin as a particularly popular rest stop. The cabin has a pit latrine and a stream used for drinking water.

Hamlet and his team swabbed the toilet and every surface, and tested the water from the stream. The water was clean, but every single swab tested positive for human fecal contamination.

The Pacific Crest Trail Association (PCTA) offers a comprehensive list of tips to help hikers avoid coming down with a nasty stomach bug. Make sure you wash your hands frequently using biodegradable soap (Dr Bronner's Peppermint Castile Liquid Soap, available from Amazon for around $10, is a favorite of ours and can serve as toothpaste on the trail). Alcohol-based hand sanitizers aren't as effective.

Avoid sharing food with others, and try not to touch your eyes, nose and mouth. Boil or chemically treat drinking water if you are worried about norovirus, and take responsibility if you do become ill. Drink plenty of fluids and seek medical advice, particularly if you are dehydrated or the symptoms last more than a few days. Wash your hands frequently and avoid touching common areas and surfaces. Stay away from others until two days after symptoms stop.

Cat Ellis

Cat is the editor of Advnture, She’s been a journalist for 15 years, and was fitness and wellbeing editor on TechRadar before joining the Advnture team in 2022. She’s a UK Athletics qualified run leader, and in her spare time enjoys nothing more than lacing up her shoes and hitting the roads and trails (the muddier, the better), usually wearing at least two sports watches.