Assessment of enteric viruses in a sewage treatment plant located in Porto Alegre, southern Brazil

Abstract

In order to verify the microbial quality of the influents and effluents of one STP from southern Brazil, an eight-month survey was conducted to examine the presence of total and fecal coliforms and of adenovirus (HAdV), enterovirus (EV), genogroup A rotaviruses (GARV) and Torque teno virus (TTV), in treated effluent samples from São João/ Navegantes STP, Porto Alegre (Brazil). A total of 16 samples were collected, eight of influent (raw sewage, prior to treatment), and the other eight of the effluent (post-treatment sewage). Total and fecal coliform levels ranging from 3.6 × 10 4 to 4.4 × 10 7 MPN/100 mL and 2.9 × 10 3 to 1.7 × 10 7 MPN/100 mL, were detected in all samples. In raw sewage, HAdV (25%) and GARV (28.6%) viral genomes were detected. The analysis of effluent samples revealed the presence of HAdV (50%), EV (37.5%), and TTV (12.5%) genomic fragments. All samples, regardless of the month analysed, presented detection of a least one virus genus, except for in April. Higher virus detection rates were observed in treated sewage samples (62.5%), and in 80% of them (effluent positive samples) HAdV was detected. Results showed that improvements in sewage monitoring and treatment processes are necessary to reduce the viral and bacterial load on the environment in southern Brazil. To the knowledge of the authors, this is the first study showing the monitoring of viral genomes in influent and effluent samples from a STP located in Porto Alegre (Rio Grande do Sul, Brazil), southern Brazil.

Surface water quality in the Sinos River basin, in Southern Brazil: tracking microbiological contamination and correlation with physicochemical parameters

“…This lack of a population × frequency relationship could be related to the presence of inhibitors in the samples of point 7, resulting from domestic sewage, which may have interfered with viral detection by qPCR. These data are in agreement with previous studies performed by our group, in which HAdV viral genomes were detected in 80 % of samples for treated sewage, 25 % of raw sewage, and 21.43 % in the stream water (Dalla Vecchia et al 2012a, b). Point 8 was the one that presented the highest load of HAdV (Fig.…”

“…Adsorption-elution concentration method that uses a negatively charged membrane (Katayama et al 2002) with minor modifications (Dalla Vecchia et al 2012a, b) was used. The obtained concentrate was aliquoted and stored in a −80°C freezer for further processing.…”

Detection of Pathogenic Viruses in Sewage Provided Early Warnings of Hepatitis A Virus and Norovirus Outbreaks

“…Since an infected person excretes 10 7 to 10 13 virus particles per day (19), analysis of incoming sewage may be a useful tool to reveal the presence of and quantify excreted fecal human pathogens and thereby give an estimation of the number of infected persons. Most studies on enteric viruses in sewage only detect the viruses and do not relate the virus sequences identified in sewage to those from patients from the same sampling time and region (27,(35)(36)(37)(38)(39)(40)(41)(42). Several of the techniques for virus detection in sewage have also been developed for detection of poliovirus in line with the WHO polio eradication program (36,(43)(44)(45)(46)(47)(48)(49).…”

Distribution and genetic diversity of the human polyomaviruses JC and BK in surface water and sewage treatment plant during 2009 in Porto Alegre, Southern Brazil

“…Monthly, two water samples were collected between March and October of 2009. These samples were collected as described in Vecchia et al (2012b). In total, eight samples of the influent, the pre-treatment sewage and eight of the effluent, post-treatment sewage were collected and analyzed.…”