As Summer Nears, 'Winter Vomiting Disease' Surges

Hikers on one of America's most iconic trails are getting an up-close lesson on what's often dubbed the "winter vomiting" bug, even as data shows it's hardly confined to winter, or to the backcountry. At least two dozen people trekking the Pacific Crest Trail near Wrightwood, California, have recently come down with what's believed to be norovirus, prompting at least one air rescue, per USA Today, citing local media reports. The highly contagious gastrointestinal virus, which brings on sudden vomiting and diarrhea, is also cropping up elsewhere: Wastewater surveillance led by Stanford found norovirus in every sample tested nationwide in May, with especially high levels in the Northeast and Midwest.

CDC figures show a modest spring bump, with roughly 12% of tests found to be positive in late April and early May. Newsweek features a map that shows where levels are now highest. Norovirus typically ramps up in late fall and peaks around March, but it never fully disappears. Outbreaks on cruise ships, in child-care centers, and in nursing homes are common, per the CDC. The virus spreads easily via tainted food, water, or surfaces, or through close contact with an infected person (even if they're asymptomatic); just a few particles can make you sick. There's no vaccine, so public health experts say the best defense remains basic: Wash hands thoroughly, handle food carefully, and sanitize frequently touched surfaces.