Viral agents are the most common causes of childhood gastroenteritis over the world. Rotaviruses, the main causative agents of viral gastroenteritis in infant and young children, are followed by other viruses, namely adenoviruses, astroviruses, noroviruses and caliciviruses. The aims of this study were to determine the frequencies of rotavirus, adenovirus and astrovirus infections in children with acute gastroenteritis in our region, and to evaluate these frequencies according to age, gender and seasonal features. A total of 363 stool specimens obtained from 182 female and 181 male children (age range: 0-6 years) who were admitted to hospital with diarrhea, during January-December 2008 in Mersin (a province located at Mediterranean coast of Turkey), were included to the study. The presence of rotavirus, adenovirus and astrovirus antigens in the samples were investigated by ELISA method (R-Biopharm RIDASC-REEN, Germany). Viral antigen positivity was detected in 44.4% (161/363) of the samples, and the positivity rates of rotavirus, adenovirus and astrovirus were 32.2% (117/363), 10.5% (38/363) and 1.7% (6/363), respectively. Rotavirus was the most frequently detected agent in children with viral gastroenteritis (117/161; 72.6%), while adenovirus was found in 23.6% (38/161) and astrovirus in 3.7% (6/161) of the cases. Two of the patients (0.6%) yielded triple viral antigen positivity in their stool samples, and 35 (9.6%) of the patients yielded two at a time. Rotavirus + adenovirus (26/363; 7.2%) associations were the most frequently detected coinfections. The difference between the rates of viral antigen positivities in males and females was statistically insignificant (p> 0.05). Rotavirus antigen positivity was detected as 23.7% in 0-12 months group (n= 97), 44.9% in 13-24 months group (n= 69), 40.3% in 25-36 months group (n= 62), 35.4% in 37-48 months group (n= 48), 30.3% in 49-60 months group (n= 33), and 20.4% in 61-72 months group (n= 54). These rates were 7.2%, 18.8%, 8.1%, 16.7%, 6.1% and 5.6%, respectively for adenovirus positivity. Of astrovirus antigen positive children, two were 0-12 months, three were 13-24 months and one was 25-36 months old. No astrovirus positivity was detected in 135 children older than 3 years. The difference between the rates of rotavirus positivities in age groups was found statistically significant (p= 0.0016); however there was no significant differences between the rates of adenovirus and astrovirus positivities (p> 0.05) according to age groups. Rotavirus infections were mainly detected in winter season, namely december (n= 17; 50%), january (n= 22; 46.8%), february (n= 21; 41.2%) and march (n= 12; 31.6%), reduced during the summer, and started to rise in november (n= 14; 38.9%). Comparatively adenovirus and astrovirus positive cases were also seen especially in fall and winter months, while no cases were detected between may to august. In conclusion, since nearly half of the childhood gastroenteritis cases (44.4%) were due to viral agents in our region, testing for the viral antigens may guide the clinical approach to the patients with acute diarrhea especially in 1-3 years old children and in winter season.
