The number of cases of food poisoning caused by the norovirus sharply surged last year, health authorities said on Thursday.

The Korea Centers for Disease Control and Prevention said a total of 49 cases of norovirus infection were reported last year, an 88.5 percent increase from 26 cases in 2011.

The virus spreads quickly, particularly during the winter time. People must wash their hands as frequently as possible until March this year to prevent further infection, the agency said.

Noroviruses are the most common causes of acute gastroenteritis, or infection of the stomach and intestines. Children, the elderly and those with a weak immune system need to take extra care to avoid infection, the KCDC added.

(christory@heraldcorp.com)