Acute Gastroenteritis Surveillance through the National Outbreak Reporting System, United States

Aron J. Hall

, Mary E. Wikswo, Karunya Manikonda, Virginia A. Roberts, Jonathan S. Yoder, and L. Hannah Gould

Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Abstract

Implemented in 2009, the National Outbreak Reporting System provides surveillance for acute gastroenteritis outbreaks in the United States resulting from any transmission mode. Data from the first 2 years of surveillance highlight the predominant role of norovirus. The pathogen-specific transmission pathways and exposure settings identified can help inform prevention efforts.

Acute gastroenteritis (AGE; defined as diarrhea or vomiting) is a major cause of illness in the United States; an estimated 179 million episodes occur annually (1). AGE is caused by a variety of viral, bacterial, and parasitic pathogens and by toxins, chemicals, and other noninfectious causes. Noroviruses are the leading cause of epidemic gastroenteritis, detected in ≈50% of AGE outbreaks across Europe and the United States (2,3). However, until 2009, national surveillance for AGE outbreaks in the United States had been limited to foodborne or waterborne disease outbreaks because no national surveillance existed for AGE outbreaks spread by other transmission modes.
To better understand and guide appropriate interventions to prevent epidemic gastroenteritis, the Centers for Disease Control and Prevention (CDC) launched a novel national surveillance system in 2009—the National Outbreak Reporting System (NORS). This system enhanced and expanded upon 2 existing surveillance systems, the Foodborne Disease Outbreak Surveillance System and the Waterborne Disease and Outbreak Surveillance System. NORS is an Internet-based system for local, state, and territorial health departments to report all outbreaks of foodborne and waterborne disease; AGE outbreaks caused by contact with infected persons, animals, or environmental sources; and AGE outbreaks caused by other or unknown modes of transmission (4). As such, NORS provides a national surveillance system for all pathways of AGE outbreaks in the United States. To assess the roles of specific pathogens, temporal trends, and exposure pathways, we summarized AGE outbreak data submitted through NORS during the first 2 years after implementation of the system.