The effluents of a sewage treatment plant may contain infectious human viruses representing a major public health issue. In the present study, an 8 months survey was conducted in order to evaluate the presence of enteroviruses (EV), adenoviruses (AdV), and hepatitis A viruses (HAV) in untreated and treated sewage samples collected from a primary treatment municipal wastewater plant, located in the northeastern Greece. Reverse transcriptase-polymerase chain reaction (RT-PCR) and nested polymerase chain reaction techniques have been applied for viral nucleic acid detection. Positive samples were confirmed by sequencing, and comparative phylogenetic analysis was performed on the isolated viral strains. EVs, AdVs, and HAV have been detected in 40% (10/25), 40% (10/25), 4% (1/25) of the samples collected from the plant's inlet, and in 12% (3/25), 44% (11/25), 0% (0/25) of the samples collected from the plant's outlet. Adenovirus types 3 (Ad3), 10 (Ad10) and 41 (Ad41), and hepatitis A virus type H2 have been recognized, while for enteroviruses Coxsackie type A2 and Echovirus types 27 and 30 have been recorded. The results suggest that treated sewage may still contain human viruses and thereby represent a potential health hazard. Moreover, their possible reuse in agriculture or elsewhere must be considered with concern. Furthermore, this study shows the usefulness of molecular methods for virus detection, typing and virological quality analysis of sewage treatment plants.

Background: In this decade, several countries have suffered from infection of humans with highly pathogenic H5N1 influenza, provoking the threat of a worldwide pandemic. Information about a spread pattern of infectious diseases such as influenza of the currently ordinary types H3N2 and H1N1 is thought to be useful for taking preventative measures against this misgiving pandemic. This study aimed to analyze annual epidemics of the ordinary influenza in Japan with network analysis and to explore spread patterns.Methods: The analyzed data was the cases of influenzalike-illness during these 20 years. We constructed the vectors of the increasing rates of the reported cases for each prefecture at each week, and calculated the matrices of the space-time correlation which was defined for all pairs of prefectures. As each correlation was treated as each tie, a valued-network was depicted, and was analyzed with network analysis. All prefectures were also classified with cluster analysis.Results: In 2007, the ties between prefectures were strong in the south-east region of Japan, and the strongest tie was that between Miyazaki and Kagoshima. Relatively strong ties could be that between geographically neighboring prefectures. On the other hand, the ties were relatively weak for a prefecture isolated from the others by seas (Hokkaido or Okinawa). The trend seemed almost similar during analyzed years.Conclusion: An epidemic could be spread within geographically neighboring prefectures connected with a strong tie. These prefectures should be targeted to organize preventative measures of pandemic of H5N1 intensively.