SELECTIVE METAGENOMIC ANALYSIS OF POSITIVE-STRAND RNA VIRUSES IN WASTEWATER

Abstract

 The presence of enteric viruses in wastewater reflects the occurrence of infectious gastroenteritis in human society. However, because the relative abundance of human viruses to whole viruses in wastewater is extremely small, it is inefficient to detect human virus with metagenomic analysis targeting whole viruses. Then, by using pyrosequencing, we developed a selective metagenomic approach targeting positive-strand RNA viruses to which many human enteric viruses belong. As a result, we detected RNA viruses consisting of 10 genera and 30 species. Among them, human viruses were classified to 3 families (Picornaviridae, Caliciviridae and Astroviridae) and 5 genera (Kobuvirus, Norovirus, Mamastrovirus, Cosavirus and Sapovirus). The ratio of sequence reads of human viruses to identified sequence reads was 23%, which was 10 times higher than other studies with metagenomic analysis targeting whole viruses. In addition, sequence reads of bacteriophages were successfully eliminated, and those of plant viruses that are abundant in municipal wastewater were significantly reduced.