THURSDAY, Jan. 24 (HealthDay News) -- A novel strain of norovirus, GII.4 Sydney, which was first detected in Australia in March of last year, was responsible for the majority of norovirus outbreaks in the United States from September through December 2012, according to a report published in the Jan. 25 issue of the U.S. Centers for Disease Control and Prevention's Morbidity & Mortality Weekly Report.
Leslie Barclay, from the CDC in Atlanta, and colleagues analyzed 2012 CaliciNet data on norovirus activity to determine the prevalence of GII.4 Sydney-associated outbreaks in the United States.
The researchers noted 266 reported outbreaks of norovirus, which is highly contagious and causes acute gastroenteritis, leading to nausea and vomiting. Of these cases, 141 (53 percent) were caused by the new strain.
"GII.4 noroviruses remain the predominant cause of norovirus outbreaks, and the GII.4 Sydney strain appears to have replaced the previously predominant strain, GII.4 New Orleans. Compared with other norovirus genotypes, GII.4 noroviruses have been associated with increased rates of hospitalizations and deaths during outbreaks," the authors write. "Health care providers and public health practitioners should remain vigilant to the potential for increased norovirus activity in the ongoing season related to the emergent GII.4 Sydney strain."