Norovirus spike hits Pacific Crest Trail hikers

The Pacific Crest Trail Association said in late May that it was working with San Bernardino County public-health officials after reports of “gastrointestinal illness” among hikers near Wrightwood, California. Multiple reports since then have identified norovirus as the illness affecting hikers on the Southern California section of the trail, with cases clustered near the San Gabriel Mountains. (yahoo.com) The outbreak has drawn attention because it hit during peak thru-hiking season on the Pacific Crest Trail, a route of roughly 2,650 miles from Mexico to Canada. (backpacker.com) News reports said at least seven hikers had confirmed norovirus and dozens more reported vomiting, diarrhea and dehydration. (cdc.gov) ### Where are hikers getting sick? Wrightwood, in San Bernardino County, is the main location tied to the reports. The Pacific Crest Trail Association said the illnesses were reported in the Wrightwood area, and local coverage placed the cluster on the San Gabriel Mountains stretch of the trail. At least one hiker was airlifted for medical care after becoming too weak to continue, according to reports cited by several outlets. (yahoo.com) KTLA said at least two dozen hikers were believed to have been affected so far. ### Is this part of a bigger national spike? CDC data updated May 20 showed 1,194 norovirus outbreaks reported by NoroSTAT-participating states from Aug. 1, 2025, through May 7, 2026, compared with 2,534 during the same period a year earlier. (backpacker.com) The CDC said the 2025-2026 total was within the middle 50% of prior seasons, not outside the historical range. NBC News reported on May 29 that wastewater surveillance showed “high” norovirus levels across much of the country. (yahoo.com) Amanda Bidwell, scientific program manager at WastewaterSCAN, told NBC that norovirus remained in the “HIGH” category nationally over the prior 21 days, while infectious-disease specialist Dr. Linda Yancey said the California activity was not unusual compared with prior seasons. (ktla.com) ### Why can norovirus spread on a trail? Norovirus spreads through contaminated food or water, shared surfaces and close contact, according to coverage citing trail and health warnings. KTLA said officials warned that even outdoor settings can allow rapid spread when hikers share campsites, restroom facilities, utensils or untreated water sources. (cdc.gov) Some reports said hikers suspected a shared water cache in Swarthout Valley as a possible link, but the source of the outbreak had not been confirmed. NewsNation and SFGATE both reported that the cause remained unknown. ### What are hikers being told to do right now? (nbcnews.com) Trail officials and news reports have urged hikers to wash hands with soap and water, avoid sharing food, utensils or water containers, and properly treat drinking water. KTLA said hikers with symptoms were being told to stay off the trail, while USA Today’s coverage described the same basic precautions for people moving through the area. (ktla.com) The Pacific Crest Trail Association has not announced a closure in the cited coverage. For now, the next concrete step is continued monitoring by the association and San Bernardino County health officials as hikers move through the Wrightwood section in early June. (yahoo.com) (ktla.com) (newsnationnow.com)