OK, so maybe you’re one of those people who don’t wash their hands even after going to the bathroom because your dad never did and he never got sick.

Or you think a three-second hand scrub is more than enough.

Or you squirt on some hand-sanitizer and figure you’ve done your duty.

I have some news for you.

There’s a new study out on norovirus and the role hand-washing can play in stopping an outbreak.

To sum it up: Wash up!

Norovirus is responsible for roughly 1 in 5 cases worldwide of acute gastroenteritis. The symptoms are pretty horrible: nausea, vomiting and diarrhea. And it’s very, very, very contagious. It takes only one particle to infect a human, compared to roughly 50 to 100 particles of flu virus.

In countries with good health-care systems, a norovirus victim will have about three days of misery but likely recover. But for young children and the elderly, especially in developing countries, the prognosis can be grim. The Centers for Disease Control and Prevention estimates that 50,000 children a year, under age 5, die from norovirus, mainly in lower-income countries.

The virus is particularly effective at finding victims in crowded places: hospitals, schools … and cruise ships, where everybody is living, eating and sharing activities in the same spaces.

Researcher Sherry Towers became curious about norovirus after contracting a case herself. She believes she got it by using a bathroom in which someone had … barfed. She thought the facility had been adequately cleaned. (Only apparently not). To read more from Marc Silver, click here.