Ottawa, May 1 (IANS): Noroviruses, a group of viruses responsible for over half of global gastroenteritis cases, can spread by air up to several metres from an infected person, warns a new study.

Gastroenteritis or infectious diarrhoea is a common condition where the stomach and intestines become inflamed.

The new findings suggest that measures applied in hospitals during gastroenteritis outbreaks may be insufficient to effectively contain this kind of infection.

"The measures applied in hospital settings are only designed to limit direct contact with infected patients," said lead researcher Caroline Duchaine, professor at the Laval University in Canada.

"In light of our results, these rules need to be reviewed to take into account the possibility of airborne transmission of noroviruses. Use of mobile air filtration units or the wearing of respiratory protection around patients with gastroenteritis are measures worth testing," Duchaine noted.

The researchers conducted the study at eight hospitals and long-term care facilities affected by gastroenteritis outbreaks. They gathered air samples at a distance of one metre from patients, at the doors to their rooms, and at nursing stations.

Noroviruses were found in the air at six of the eight facilities studied. The viruses were detected in 54 percent of the rooms housing patients with gastroenteritis, 38 percent of the hallways leading to their rooms, and 50 percent of nursing stations.

Virus concentrations ranged from 13 to 2,350 particles per cubic meter of air.

A dose of 20 norovirus particles is usually enough to cause gastroenteritis.

The study appeared in the journal Clinical Infectious Diseases.