Norovirus clusters are resistant to environmental stresses and UV disinfection, new study finds

Clusters of a virus known to cause stomach flu are resistant to detergent and ultraviolet disinfection, according to new research co-led by Danmeng Shuai, a civil and environmental engineer at the George Washington University, and Nihal Altan-Bonnet, head of the Laboratory of Host-Pathogen Dynamics at the National Heart, Lung, and Blood Institute. The findings suggest the need to revisit current disinfection, sanitation and hygiene practices aimed at protecting people from noroviruses.

Noroviruses are the leading cause of gastroenteritis around the world, with more than 21 million cases each year in the United States alone.

In the U.S. National Science Foundation-funded research, Shuai, Altan-Bonnet and the study's first author Mengyang Zhang of GWU looked at the behavior of these virus clusters in the environment. They found that the virus could survive attempts to disinfect with detergent solutions or even UV light. Many water treatment plants use UV light to kill noroviruses and other pathogens.

"These membrane-cloaked viruses are tricky," Shuai said. "Past research shows they can evade the body's immune system and that they are highly infectious. Our study shows that these membrane-enclosed viruses are also able to dodge efforts to kill them with standard disinfectants."

Altan-Bonnet added, "We have to consider these viral clusters cloaked in vesicle membranes as unique infectious agents in the public health arena. When it comes to virulence -- and now with this study, disinfection and sanitation -- the sum is much more than its parts. And these clusters are endowed with properties that are absent from other types of viral particles."

According to the researchers, future studies must be done to find out if certain kinds of cleaning solutions or higher dosages of UV light would degrade the protective membrane or kill the viruses inside. Ultimately, the research could be used to devise more effective disinfection methods to clean surfaces at home, in restaurants and in places where norovirus can spread and cause outbreaks, such as on cruise ships.

The study was published in the journal Environmental Science & Technology.