First molecular detection of group A rotavirus in urban and hospital sewage systems by nested-RT PCR in Shiraz, Iran

Background: Group A rotaviruses are the most significant cause of acute gastroenteritis in children worldwide. Rotaviruses are shed in high numbers and dispersed widely throughout bodies of water in the environment. This represents a significant health hazard for humans, mainly due to the stability of the viruses during wastewater treatment processes. This study was conducted to evaluate the prevalence of rotaviruses, to determine G genotypes of circulating rotaviruses and to assess the efficiency of rotavirus removal in urban and hospital sewage treatment plants in Shiraz, Iran. Materials and methods: During the period from October 2010 to June 2011, a total of sixty sewage samples from urban and hospital sewage disposal systems were collected by Grab Sampling in Shiraz, Iran. All the samples were concentrated in pellet form and two-phase methods and then group A rotaviruses were investigated with enzyme immunoassays (EIA). Rotavirus-positive specimens were genotyped by the nested RT-PCR and by using different types of specific primers. Results: In total, rotaviruses were identified in 25% (15 cases) of sewage samples, representing 73.33% (11 cases) of influent and 26.67% (4 cases) of effluent systems. The frequency of rotavirus detection in autumn, winter and spring was 46.67%, 33.33% and 20%, respectively (P= 0.004). The most common circulating genotype was G1 (73.33%), followed by G1G4 (20%) and non-typeable (6.67%), respectively. Conclusions: The high prevalence of rotaviruses in urban and hospital sewage systems highlights the importance of environmental surveillance as a tool to detect new genotypes and to investigate the epidemiology of rotaviruses circulating in the community.