Rotavirus epidemiology of children in Bursa, Turkey: a multi-centered hospital-based descriptive study

In this multi-centered study, we aimed to evaluate the distributional incidence of rotavirus acute gastroenteritis (RVAGE) according to age groups and epidemiological features of hospitalized and outpatient cases in the city center of Bursa, Turkey. This study was carried out in a multi-centered setting that included the four largest hospitals dealing with more than 90% of the pediatric population in Bursa. Children under 15 years old with acute gastroenteritis (AGE) were included in the study. During a period of one year, all of the hospitalized AGE cases and initially one out of 15 systematically determined outpatien cases with AGE were included in the study. RV diagnosis was made by using monoclonal RV antigen kits (BioMêrieux, France) in fresh stool. Of 542,199 annual general hospital visits in those four hospitals, 5,988 were diagnosed with AGE (1.1%). The annual general AGE incidence in children under 15 years of age was found to be 1.7% per year. The annual incidence of RVAGE was 2.8%, 2.5%, 1.5%, and 0.14% in the cases aged < 1 year, < 2 years, < 5 years, and 5-14 years, respectively. The hospitalization rate of RVAGE was estimated to be 22.5%, 27%, 20%, and 12.5% in the cases aged < 1 year, < 2 years, < 5 years, and 5-14 years, respectively. RVAGE comprised 21% of the outpatient AGE cases and 0.35% of the total general pediatric outpatient cases. Acute gastroenteritis (AGE)-related hospitalizations comprised 5.7% and RVAGE-related hospitalizations 1.6% of all hospitalizations. RVAGE comprised 28.5% of all AGE hospitalizations. It was found that the annual RVAGE-related hospitalization incidence was 629/100,000 in those aged < 1 year, 553/100,000 in those aged < 2 years, 293/100,000 in those aged < 5 years, and 17/100,000 in those aged 5-14 years. Rotavirus acute gastroenteritis (RVAGE) in both hospitalized and outpatient cases was found to be higher (60%) in boys than girls. It was found that the RV positivity in hospitalized AGE cases was higher than in outpatient AGE cases (28.5% vs. 21%, p = 0.002). Eighty-six percent of hospitalized and 76% of outpatient RVAGE cases were < 5 years (p = 0.018). When the monthly distribution of RVAGE was examined in hospitalized and outpatient cases, it was found that RVAGE increased rapidly after October and decreased after March in cases aged < 5 years. The highest RV positivity rate was detected as 49.5% in January in hospitalized AGE cases and 31.5% in February for outpatient cases. In those < 5 years, the lowest RV positivity rate was detected in the June-September period both in hospitalized (between 11-25%) and in outpatient (between 0-18%) cases. Nearly half (47%) of the hospitalized RVAGE in those < 5 years were hospitalized in the January-March period. More than half of the outpatient RVAGE cases (55%) aged < 5 years were detected in the January-March period. No meaningful differences were found in the monthly distribution and in the monthly RV positivity rates between hospitalized and outpatient cases. In conclusion, RV was found to be a significant etiologic agent in hospitalize (28.5%) and outpatient (21%) AGE cases in Bursa. Nearly 80% of the RVAGE cases were aged < 5 years. Approximately half of the cases were seen in the January-March period. In January, half of the hospitalized cases and one-third of the outpatient AGE cases were RVAGE. Our findings have revealed a comparable pattern in RVAGE epidemiology in Bursa to that of the European countries and the United States.