Abstract Title
Norovirus Shedding in Symptomatic and Asymptomatic Patients: Insights from a Tertiary Care Hospital-Based Study in Bangladesh
Presenter
Syed Moinuddin Satter, icddr,b
Co-Author(s)
Sharmeen Akhter Urmi, International Centre for Diarrhoeal Disease Research, Bangladesh;
Farzana Fariha, International Centre for Diarrhoeal Disease Research, Bangladesh;
Shahreen Rahman, International Centre for Diarrhoeal Disease Research, Bangladesh;
Md. Mahfuzur Rahman, International Centre for Diarrhoeal Disease Research, Bangladesh;
Probir Kumar Ghosh, International Centre for Diarrhoeal Disease Research, Bangladesh;
Mohammad Enayet Hossain, International Centre for Diarrhoeal Disease Research, Bangladesh;
Mustafizur Rahman, International Centre for Diarrhoeal Disease Research, Bangladesh;
Rashi Gautam, Center for Disease Control and Prevention, Atlanta, Georgia, USA;
Jan Vinjé, Center for Disease Control and Prevention, Atlanta, Georgia, USA;
Adiba Hassan, Center for Disease Control and Prevention, Atlanta, Georgia, USA;
Sara A. Mirza, Center for Disease Control and Prevention, Atlanta, Georgia, USA;
Paul A. Gastañaduy, Center for Disease Control and Prevention, Atlanta, Georgia, USA;
Syed M. Satter, International Centre for Diarrhoeal Disease Research, Bangladesh; and
Umesh D. Parashar, Center for Disease Control and Prevention, Atlanta, Georgia, USA.
Abstract Category
Epidemology
Abstract
Background. The frequent detection of norovirus in the stool of healthy persons may be due to prolonged shedding of norovirus after recovery from illness. We describe the duration of norovirus shedding in symptomatic and asymptomatic persons in Bangladesh.
Methods. We enrolled acute gastroenteritis (AGE) cases and non-AGE controls (matched by age, sex, season, and site) in two hospitals during January 18–September 30, 2023. Norovirus testing by real-time RT-PCR was performed on fecal samples obtained at enrollment, and among those that tested positive, at days 20, 40, 60, and 120. The duration of shedding was defined as the interval (in days) between the first and last genogroup congruent norovirus-positive specimen. Cycle threshold (Ct)-values were used as an inverse measure of the viral load.
Results. At enrollment, 12 of 32 AGE cases and 5 of 28 non-AGE controls were norovirus positive. Among AGE cases and non-AGE controls, 5 (42%) and 2 (40%) remained positive for 20 days or more, and the duration of norovirus shedding ranged between 0 to 119 and 0 to 63 days, respectively. Ct-values did not increase with each consecutive specimen for two AGE cases and one non-AGE control. Across sampling timeframes, Ct-values of AGE cases and non-AGE controls overlapped. GII.4 Sydney[P16] was detected in 20 (71%) of 28 positive specimens; 7 were genogroup II (untypeable) and one typed as GII.3[P16].
Conclusions. Prolonged norovirus shedding can occur post-hospitalization even among patients without AGE symptoms. Whether asymptomatic shedding poses a risk for ongoing norovirus transmission requires further evaluation.
Methods. We enrolled acute gastroenteritis (AGE) cases and non-AGE controls (matched by age, sex, season, and site) in two hospitals during January 18–September 30, 2023. Norovirus testing by real-time RT-PCR was performed on fecal samples obtained at enrollment, and among those that tested positive, at days 20, 40, 60, and 120. The duration of shedding was defined as the interval (in days) between the first and last genogroup congruent norovirus-positive specimen. Cycle threshold (Ct)-values were used as an inverse measure of the viral load.
Results. At enrollment, 12 of 32 AGE cases and 5 of 28 non-AGE controls were norovirus positive. Among AGE cases and non-AGE controls, 5 (42%) and 2 (40%) remained positive for 20 days or more, and the duration of norovirus shedding ranged between 0 to 119 and 0 to 63 days, respectively. Ct-values did not increase with each consecutive specimen for two AGE cases and one non-AGE control. Across sampling timeframes, Ct-values of AGE cases and non-AGE controls overlapped. GII.4 Sydney[P16] was detected in 20 (71%) of 28 positive specimens; 7 were genogroup II (untypeable) and one typed as GII.3[P16].
Conclusions. Prolonged norovirus shedding can occur post-hospitalization even among patients without AGE symptoms. Whether asymptomatic shedding poses a risk for ongoing norovirus transmission requires further evaluation.