Norovirus sickens Pacific Crest Trail hikers

Newsweek reported on May 20 that a norovirus outbreak near Wrightwood, California, sickened roughly two dozen hikers on the Pacific Crest Trail, citing local reporting from SFGate. The illnesses began surfacing around May 8 along the Southern California section of the 2,650-mile trail, which runs from Mexico to Canada. SFGate reported that at least seven hikers were told by medical providers in nearby towns that they had norovirus after seeking treatment. No official public case count had been released in the reports reviewed. ### Where on the trail are hikers getting sick? Wrightwood, California, is the area most closely tied to the outbreak in published reports, with illnesses reported on the Pacific Crest Trail near the town about an hour northeast of Los Angeles. Newsweek said early signs pointed to a shared water cache in the Wrightwood area, specifically Swarthout Valley between Cajon Pass and Mount Baden-Powell, as a possible contamination source, though the source had not been confirmed. SFGate reported that members of the trail community began discussing sick hikers around May 8. The outlet said people treated at urgent care facilities in Hesperia and Victorville were told they had norovirus, and hiking partners later developed similar symptoms. ### How many hikers were affected, and how serious was it? SFGate reported that roughly two dozen hikers had reported symptoms and that at least seven had received a confirmed diagnosis from medical professionals. (newsweek.com) Newsweek repeated those figures and said the outbreak had led to at least one air rescue after a hiker became too ill to continue. Ron Hals, a 73-year-old hiker, told SFGate he had “never been that weak,” adding that he went from feeling strong to struggling to stand within about an hour, according to Newsweek’s account of the reporting. (sfgate.com) SFGate described the outbreak as severe enough to prompt rural communities to take precautions aimed at protecting public health. ### Why does a shared water cache matter? (sfgate.com) Newsweek said a shared water cache in Swarthout Valley was being treated as a possible source because many sick hikers had passed through the same area. The report said the source was not confirmed. In long-distance hiking, caches are commonly left for hikers in dry stretches, which can create repeated contact with the same containers, spigots or nearby surfaces. That last point is an inference from how shared caches function, not a confirmed finding in this outbreak. (newsweek.com) The CDC says norovirus spreads through contaminated food or water, contaminated surfaces, and close contact with an infected person. SFGate reported that remote outdoor settings can make sanitation harder, which can increase the chance of spread when hikers share supplies or campsites. ### What exactly is norovirus, and why is it hard to control outdoors? The CDC says norovirus is very contagious and typically causes diarrhea, vomiting, nausea and stomach pain. (newsweek.com) Symptoms usually begin 12 to 48 hours after exposure, and dehydration can become a risk, especially when vomiting and diarrhea are severe. CDC guidance says soap-and-water handwashing works better against norovirus than hand sanitizer alone. (cdc.gov) Newsweek and SFGate both noted that hand sanitizer cannot be relied on to kill the virus, and the CDC recommends cleaning contaminated surfaces appropriately, including with bleach-based disinfection in many settings. ### Is this part of a broader surge? CDC outbreak surveillance data updated April 29 showed 1,092 norovirus outbreaks reported by NoroSTAT-participating states from Aug. 1, 2025, through April 9, 2026. (cdc.gov) The CDC said that total was within the middle 50% of seasonal outbreak counts reported in the same period during 2012-2025, which does not by itself indicate an unusually high national season. The Pacific Crest Trail Association’s website lists trail conditions, closures and safety information for hikers, though the outbreak reports reviewed did not show a formal trail-wide closure tied to the illnesses. (cdc.gov) As hikers continue through the Wrightwood-area section, the most immediate next step is likely to be more case reporting through local providers and trail networks rather than a single official tally. (pcta.org) (cdc.gov)