The presence of infectious viral particles in water samples of different types and locations of Rio Grande do Sul, Brazil

Abstract

The parameters for drinking water currently are based only on the analysis of bacteria; nevertheless the absence of coliforms does not exclude viral contamination. Enteric viruses may resist conventional water and sewage treatment methods, due to its physical and chemical stability. Although laborious and time consuming, analysis by viral isolation in cell culture allows to evaluate the viability of viral particles, advantageous feature when compared to molecular biology techniques. Sixty-four water samples from surface and tap water from various Rio Grande do Sul’s locations were collected and inoculated into 24-well microplates containing CER cell line cells. The microplates were stored in 37°C oven, 5% CO2 for seven days and observed daily for possible detection of cytopathic effect (CPE) in inverted microscope. CPE consistent with viral presence was observed in 12 (21.8%) of 55 samples, with higher prevalence in tap water, indicating the need to revise our current legislation on drinking water.