In July, 2014 a norovirus outbreak linked to a lake near Portland, Oregon sickened 70 people. Those who swam in the lake were 2.3 times more likely to develop vomiting or diarrhea than those who visited the park but didn’t go in the water.

More than half of those who got ill were children between 4–10 years old. Experts believe the outbreak began after a swimmer infected with norovirus had diarrhea or vomited in the water and other swimmers swallowed the contaminated water. To prevent other people from getting sick, park officials closed the lake to swimmers for 10 days.

“Children are prime targets for norovirus and other germs that can live in lakes and swimming pools because they’re so much more likely to get the water in their mouths,” said Michael Beach, Ph.D, CDC’s associate director for healthy water. “Keeping germs out of the water in the first place is key to keeping everyone healthy and helping to keep the places we swim open all summer.”

 Norovirus Outbreak Associated with a Natural Lake Used for Recreation — Oregon, 2014

15.may.15

Morbidity and Mortality Weekly Report

Amy Zlot, MPH, Maayan Simckes, MPH, Jennifer Vines, MD, Laura Reynolds, MPH, Amy Sullivan PhD, Magdalena Kendall Scott, MPH, J. Michael McLuckie, Dan Kromer, MPA, Vincent R. Hill, PhD, Jonathan S. Yoder, MPH, Michele C. Hlavsa, MPH

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6418a2.htm?s_cid=mm6418a2_e