Health officials at the Centers for Disease Control and Prevention said Thursday that a new strain of a highly contagious norovirus is now hitting the U.S. after outbreaks in other countries severely sickened people around the globe. This new stomach bug strikes during a worse-than-usual flu season that has spread to more than 90 percent of the U.S.
During the last four months of 2012, the GII.4 Sydney strain of norovirus has resulted in over 50 percent of outbreaks of the illness. The proportion of outbreaks caused by the new strain increased significantly from 19 percent in September to 58 percent in December, according to the CDC, which continues to work with other states to monitor this strain closely.
The norovirus, similar to influenza-like illness, mutates quickly, resulting in a new strain every few years, according to infectious disease expert Dr. William Schaffner of Vanderbilt University. “What that means is more of us are susceptible,” he said, explaining that people who have had previous versions of the vomiting- and diarrhea-inducing bug are more likely to get it again.
Schaffner also said the virus is very contagious, and is often carried in the air after projectile vomiting, or lingering on surfaces where it infects the next victim.
According to the CDC, norovirus is the leading cause of acute gastroenteritis in the U.S., affecting more than 21 million people a year and leading to about 800 deaths.
Individuals infected with norovirus often report feeling miserably sick to their stomach, although the infection usually lasts just a few days. However, norovirus can cause serious complications due to dehydration from rapid fluid loss. Those especially at risk are young children and the elderly.
Dehydration can cause blood pressure to drop, which can cause fainting and falls.
CDC officials advised health workers to be vigilant for increases in norovirus outbreaks this winter because of the new GII.4 Sydney strain. They should follow standard infection control practices to prevent norovirus.
The CDC also advises the public to exercise common sense practices to help protect against norovirus, such as washing hands frequently with soap and water, disinfecting surfaces, rinsing fruits and vegetables, cooking shellfish thoroughly and not preparing food or caring for others while ill.
CDC officials said it’s too early to tell whether the new strain will lead to more outbreaks or more serious illness, but they’re watching the situation closely.