Adenovirus, enterovirus and thermotolerant coliforms in recreational waters from Lake Guaíba beaches, Porto Alegre, Brazil

Environmental and Adaptive Changes Necessitate a Paradigm Shift for Indicators of Fecal Contamination

Changes in the occurrence, distribution, and seasonal variation of waterborne pathogens due to global climate change may increase the risk of human exposure to these microorganisms, thus heightening the need for more reliable surveillance systems. Routine monitoring of drinking water supplies and recreational waters is performed using fecal indicator microorganisms, such as Escherichia coli , Enterococcus spp., and coliphages. However, the presence and numbers of these indicators, especially E. coli and Enterococcus spp., do not correlate well with those of other pathogens, especially enteric viruses, which are a major cause of waterborne outbreaks associated with contaminated water and food, and recreational use of lakes, ponds, rivers, and estuarine waters. For that reason, there is a growing need for a surveillance system that can detect and quantify viral pathogens directly in water sources to reduce transmission of pathogens associated with fecal transmission. In this review, we present an updated overview of relevant waterborne enteric viruses that we believe should be more commonly screened to better evaluate water quality and to determine the safety of water use and reuse and of epidemiological data on viral outbreaks. We also discuss current methodologies that are available to detect and quantify these viruses in water resources. Finally, we highlight challenges associated with virus monitoring. The information presented in this review is intended to aid in the assessment of human health risks due to contact with water sources, especially since current environmental and adaptive changes may be creating the need for a paradigm shift for indicators of fecal contamination.

'Don't put your head under water': enteric viruses in Brazilian recreational waters

Like in many other countries, virologic analyses are not routinely performed in Brazil in monitoring water quality for recreational purposes. We surveyed current research regarding viral contamination of recreational water environments in Brazil. Among the enteric viruses studied in Brazilian recreational waters, we highlight adenoviruses, rotaviruses, enteroviruses and noroviruses. Although there has been relatively little research on outbreaks related to bathing in recreational water environments in Brazil, noroviruses and adenoviruses are the viruses that are most often related to outbreaks. Better surveillance of the occurrence of enteric viruses in water could improve the assessment of risk to human health as well as indicate the sources of contamination and thus demonstrate the importance of adequate environmental sanitation.

Assessment of diversity of adenovirus DNA polymerase gene in recreational waters facilitated by ultracentrifugal concentration

Adenoviruses (AdV) are related to respiratory and gastrointestinal diseases in animals and human beings. Their wide genetic diversity in water bodies and their resistance to environmental conditions allow the use of AdV as a reliable marker for detection of fecal contamination. In this work, the diversity of AdV along Belo Stream - in the city of Caxias do Sul, Rio Grande do Sul, Brazil - was evaluated. Samples were compared in both concentrated and unconcentrated forms. The identification of different AdV species was performed by amplifying a partial sequence of the DNA polymerase gene. AdV was detected in 24 out of 55 concentrated samples (43.6%) and the following species were identified: human adenovirus (HAdV) species C (4/55; 7.2%), D (6/55; 10.9%), E (2/55; 3.6%), and F (9/55; 16.3%). AdV related to other mammalian hosts, such as bovine adenovirus (1/55, 1.8%) and murine adenovirus (2/55, 3.6%), have also been identified; 23.6% (13/55) of the unconcentrated samples were positive, and identified as HAdV species C (6/55, 10.9%), D (1/55, 1.8%), and F (6/55, 10.9%). Results obtained evidenced the presence and the great diversity of AdV, mainly of human origin, circulating in Belo Stream. As expected, the concentration step performed helped to detect AdV in more samples.

Enteric viruses and adenovirus diversity in waters from 2016 Olympic venues

Rio de Janeiro's inner and coastal waters are heavily impacted by human sewage pollution for decades. Enteric viruses, including human adenoviruses (HAdV), human enterovirus (EV), group A rotavirus (RV) and hepatitis A virus (HAV) are more likely to be found in contaminated surface waters. The present work aimed to assess the frequency and loads of EV, HAdV-C and -F species, RV and HAV in sand and water samples from venues used during the 2016 Summer Olympics and by tourists attending the event. Sixteen monthly collections were carried out from March 2015 to July 2016 in 12 different sites from Rio de Janeiro, Brazil. Total and thermotolerant coliform counting was performed along molecular detection of virus was performed using quantitative polymerase chain reaction (qPCR). Analyses of all samples were further investigated by integrated cell culture PCR to check about the presence of HAdV infectious virus particles. The results show that 95.9% of water samples showed contamination with at least one type of virus. Regarding the viruses individually (% for water and sand respectively): HAdV-C (93.1%-57.8%), HAdV-F (25.3%-0%), RV (12.3%-4.4%), EV (26.7%-8.8%) and HAV (0%). The viral loads ranged from 10³gc/L up to 10⁹gc/L (water), and 10³gc/g to 10⁶gc/g (sand). In the phylogenetic tree, were classified into four main clusters, referring to species C, D, F and BAdV. And up to 90% of sites studied presented at least once presence of infectious HAdV-C. The most contaminated points were the Rodrigo de Freitas Lagoon, where Olympic rowing took place, and the Marina da Glória, the starting point for the sailing races, demonstrating serious problem of fecal contamination of water resources and threatens the health of Olympic athletes, tourists and residents.

FRNA Bacteriophages as Viral Indicators of Faecal Contamination in Mexican Tropical Aquatic Systems

A particular challenge to water safety in populous intertropical regions is the lack of reliable faecal indicators to detect microbiological contamination of water, while the numerical relationships of specific viral indicators remain largely unexplored. The aim of this study was to investigate the numerical relationships of FRNA-bacteriophage genotypes, adenovirus 41, and human adenoviruses (HADV) in Mexican surface water systems to assess sewage contamination. We studied the presence of HADV, HADV41 and FRNA bacteriophage genotypes in water samples and quantified by qPCR and RT-qPCR. Virus and water quality indicator variances, as analyzed by principal component analysis and partial least squared regression, followed along the major percentiles of water faecal enterococci. FRNA bacteriophages adequately deciphered viral and point source water contamination. The strongest correlation for HADV was with FRNA bacteriophage type II, in water samples higher than the 50^th percentiles of faecal enterococci, thus indicating urban pollution. FRNA bacteriophage genotypes I and III virus indicator performances were assisted by their associations with electrical conductivity and faecal enterococci. In combination, our methods are useful for inferring water quality degradation caused by sewage contamination. The methods used have potential for determining source contamination in water and, specifically, the presence of enteric viruses where clean and contaminated water have mixed.