'Cruise Ship' Norovirus Bug Can Spread by Air, Study Finds

Current containment strategies may need adjusting, research suggests

By Mary Elizabeth Dallas

Wednesday, May 6, 2015

WEDNESDAY, May 6, 2015 (HealthDay News) -- Noroviruses -- those notorious stomach bugs that have infected scores of people and ruined countless cruise ship vacations -- can spread through the air and infect people several feet away, according to new research.

These findings suggest that current safety precautions implemented to control noroviruses may not be enough. The study also helps explain why outbreaks of the illness are difficult to contain, the researchers said.

"The measures applied in hospital settings are only designed to limit direct contact with infected patients," the study's leader, Caroline Duchaine, a professor at Universite Laval's Faculty of Science and Engineering in Quebec, Canada, said in a university news release.

"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 said.

Noroviruses are responsible for about 50 percent of cases of gastroenteritis -- a condition commonly called "stomach flu." But, the flu virus isn't actually involved in this illness at all.

Gastroenteritis occurs when the lining of the digestive tract becomes inflamed by a virus, bacteria or parasite, according to the U.S. National Library of Medicine. Symptoms include diarrhea, vomiting, abdominal pain and fever.

The new study was conducted at eight hospitals and long-term care facilities involved in an norovirus outbreak. Researchers collected air samples about three feet away from patients with the illness. They tested areas such as by the door of patient rooms and at nursing stations.

Airborne noroviruses were identified at six of the eight facilities included in the study. These germs were found in 54 percent of the sick patients' rooms. They were also found in 38 percent of the hallways leading to these rooms and at 50 percent of the nursing stations.

Concentrations of the virus ranged from 13 to 2,350 particles per cubic meter of air. The study authors pointed out that a dose of just 20 norovirus particles is usually enough to infect someone.

The study was published online recently in the journal Clinical Infectious Diseases.

SOURCE: Universite Laval, news release, April 30, 2015

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