Objective: To describe factors associated with a rectal swab or stool sample positive for norovirus, rotavirus, or adenovirus.
Design: Retrospective study.
Setting: Charleston Area Medical Center, a regional academic medical center in Charleston, West Virginia.
Methods: Rectal swab or stool samples were obtained from patients suspected of having viral gastroenteritis. These samples were sent to the Charleston Area Medical Center virology laboratory for testing in 2007. Viral antigen in rectal swab and stool samples is detected by use of commercially available immunoassay kits for each virus. Data were extracted from the virology laboratory database for the following 1-year time period: January 1, 2007, through December 31, 2007. When necessary, additional information was obtained from electronic administrative data on patients.
Results: There were 2,867 rectal swab and stool samples available for viral testing. Of these samples, 1,261 (44%) were positive for a virus. Of these positive samples, 972 (77%) were positive for norovirus, 182 (14%) were positive for rotavirus, and 110 (9%) were positive for adenovirus. The patients in the youngest age group had the highest number of test results positive for all 3 viruses. When the test results for the youngest age group (0-9 years) were compared with those for all the other age groups combined (10-99 years), the proportion of positive cases was highest for the youngest age group (P<.001). There were significant seasonal trends for all 3 viruses. Multivariate analysis of norovirus showed that season, source, sex, and age were significant predictors of a positive test result. Multivariate analysis of rotavirus showed that season and source were significant predictors of a positive test result. Multivariate analysis of adenovirus showed that season and age were significant predictors of a positive test result.
Conclusions: We conclude (1) that these 3 viruses are common causes of gastroenteritis in Charleston, West Virginia; (2) that infants and young children are more likely to test positive for these viruses than are older individuals; (3) that norovirus was the most common cause of gastroenteritis; and (4) that there are seasonal trends for all 3 viruses.