Located on the south fork of the Tuolumne River, the Tuolumne Family Camp near Yosemite couldn't be any more Norman Rockwell if it tried. Kids in rafts and playing hoops, families just hanging out.

But, this week -- the river isn't the most popular watering hole at the camp.

The sink is.

The city of Berkeley-owned camp was shut down for a 48-hour dousing with bleach after 75 of 250 campers came down with the Norovirus.

“When we go camping it's usually the bears and snakes and bugs that gather our attention, but that's because they're visible and kind of fun - the Norovirus is neither visible or fun,” said Dr. Todd Stold with Tuolumne County Public Health.

The highly contagious symptoms of nausea, vomiting and diarrhea tore through the picturesque camp with a vengeance - for a few reasons. When the population density is shoulder to shoulder, and when the little petri dishes weren't washing their hands as often, it becomes a hotbed for germs.

The closure caught this family off guard. “We came, we got here and there was a big crowd by the gate and when we asked what was going on, and they said ‘well, we've been closed for three days because of the stomach flu,’” said Willy Stern, from Los Angeles.

Though, mom was less surprised and less worried. “It's pretty amazing considering there are so many kids and it's so outdoorsy and we all eat together and there's bound to be something lurking around,” she said.

Not far from Tuolumne Family, Camp Mather was also hit by the Norovirus, though less severely.

Tuolumne public health officials believe that one of the campers brought it with them to the camp and began sharing just a little too much.