Notes from the Field: Norovirus Outbreaks Reported Through NoroSTAT — 12 States, August 2012–July 2022

Abstract

Norovirus is the leading cause of acute gastroenteritis in the United States (1). In April 2020, the incidence of norovirus outbreaks in the United States declined substantially, likely because of implementation of COVID-19-related nonpharmaceutical interventions, such as facility closures, social distancing, and increased hand hygiene (2). Similar declines were observed in other countries (3,4). Norovirus outbreaks in the United States increased rapidly starting in January 2022, approaching prepandemic (i.e., 2012-2019) levels. Norovirus transmission can be prevented by thorough handwashing and proper cleaning and disinfection of contaminated surfaces.In 2012, CDC established the Norovirus Sentinel Testing and Tracking Network (NoroSTAT) to improve timeliness and completeness of surveillance for norovirus outbreaks that occur in the United States. NoroSTAT is a collaboration between CDC and 12 state health departments.* Outbreaks are defined as two or more cases of illness associated with a common exposure. NoroSTAT-participating states report a minimum set of data elements † to the National Outbreak Reporting System § for all confirmed norovirus outbreaks (i.e., outbreaks with two or more laboratory-confirmed norovirus cases) and suspected norovirus outbreaks (i.e., outbreaks with fewer than two laboratory-confirmed norovirus cases) within 7 business days of notification. These states also upload typing information for norovirus-positive outbreak specimens to CaliciNet, ¶ the national norovirus laboratory surveillance network, within 7 business days of receipt of two *

The indelible toll of enteric pathogens: Prevalence, clinical characterization, and seasonal trends in patients with acute community-acquired diarrhea in disenfranchised communities

“…are the major causes of diarrheal diseases and death [6]. Furthermore, norovirus infections are the principal cause of foodborne disease outbreaks and are associated with approximately 20% of diarrhea cases, with similar prevalence in both children and adults [13,14]. Hundreds of millions of people across the globe are estimated to have clinically diagnosable campylobacteriosis and giardiasis annually [15], while cholera continues in disaster-and war-inflicted countries such as Yemen [16], South Sudan [17], and recently Syria and Lebanon [18], with an estimated annual toll of 1.3-4.0 million cases globally [19].…”

Outbreak of Acute Gastroenteritis Among Rafters and Backpackers in the Backcountry of Grand Canyon National Park, April–June 2022

“…Previous norovirus outbreaks have occurred among river rafters in Grand Canyon associated with contaminated food products ( 7 ) and person-to-person transmission ( 8 ) resulting in recommendations to adhere to strict hygiene guidance. An increase in norovirus activity was observed at a national level in spring 2022, with the number of outbreak reports returning to prepandemic levels for the first time since March 2020 ( 9 ).…”

Acute Gastroenteritis Outbreak Among Colorado River Rafters and Backpackers in the Grand Canyon, 2022

“…1,2 Norovirus is also the most identified source pathogen among acute gastroenteritis (AGE) outbreaks. 3,4 A review of US AGE outbreaks from 2009-2019 found that 62% were spread primarily by person-to-person contact. 3 Norovirus transmissibility can be reduced by handwashing with soap and water, avoiding food preparation until ≥48 h after symptoms end, and proper cleaning and disinfection of contaminated surfaces.…”