The Etiology of Severe Acute Gastroenteritis Among Adults Visiting Emergency Departments in the United States

Background. Acute gastroenteritis (AGE) remains a common cause of clinic visits and hospitalizations in the United States, but the etiology is rarely determined. Methods. We performed a prospective, multicenter emergency department—based study of adults with AGE. Subjects were interviewed on presentation and 3—4 weeks later. Serum samples, rectal swab specimens, and/or whole stool specimens were collected at presentation, and serum was collected 3—4 weeks later. Fecal specimens were tested for a comprehensive panel of viral, bacterial, and parasitic pathogens; serum was tested for calicivirus antibodies. Results. Pathogens were detected in 25% of 364 subjects, including 49% who provided a whole stool specimen. The most commonly detected pathogens were norovirus (26%), rotavirus (18%), and Salmonella species (5.3%). Pathogens were detected significantly more often from whole stool samples versus a rectal swab specimen alone. Nine percent of subjects who provided whole stool samples had >1 pathogen identified. Conclusions. Viruses, especially noroviruses, play a major role as agents of severe diarrhea in adults. Further studies to confirm the unexpectedly high prevalence of rotaviruses and to explore the causes of illness among patients from whom a pathogen cannot be determined are needed. Studies of enteric pathogens should require the collection of whole stool samples.