Norovirus is the leading cause of acute gastroenteritis in children

According to a new study published in the New England Journal of Medicine, norovirus is now the leading causes of acute gastroenteritis in children younger than five seeking medical care.

Between 2009 and 2010, norovirus was responsible for approximately one million pediatric medical care visits in the United States, accounting for hundreds of millions of dollars in treatment costs every year.

"Infants and young children are very susceptible to norovirus infections, which often result in a high risk of getting dehydrated from the sudden onset of intense vomiting and severe diarrhea," Dr. Daniel Payne, an epidemiologist in the Division of Viral Diseases at the Centers for Disease Control and Prevention, said. "Our study estimates that one in 278 U.S. children will be hospitalized for norovirus illness by the time they turn five years of age. It is also estimated that about one in 14 children will visit an emergency room and one in six will receive outpatient care for norovirus infections."

The study tracked 141,000 infants and young children in three U.S. counties between October 2008 through September 2010 who required medical care for acute gastroenteritis. Norovirus was detected in 21 percent, or 278 cases, of the 1,295 cases of acute gastroenteritis, while rotavirus was identified in 152, or 12 percent, of cases.

Approximately 50 percent of the medical care visits due to norovirus infections were in children between the ages of six and 18 months, while infants and one-year-olds were more likely to be hospitalized than older children.

Overall rates of norovirus in emergency rooms and outpatient offices were 20 to 40 times higher than hospitalization rates.

The researchers estimate that nationally there were 14,000 hospitalizations, 281,000 emergency room visits and 627,000 outpatient visits in 2009 and 2010 in children younger than five years of age as a result of norovirus.