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Publication
Deteção de vírus entéricos por real-time RT-qPCR em águas superficiais, subterrâneas, de consumo e águas residuais
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Advisor(s)
Abstract(s)
A água é essencial à vida, e por isso torna-se absolutamente necessário
protegê-la e assegurar a sua disponibilidade e qualidade para os
diversos fins a que se destina. De uma perspetiva microbiológica, a avaliação
e monitorização da qualidade da água são usualmente efetuadas
recorrendo a bactérias indicadoras de contaminação fecal (FIB) como
Escherichia coli ou Enterococcus spp., atuando como potenciais indicadores
da presença de agentes patogénicos. No entanto, a ocorrência
destes indicadores nem sempre se correlaciona com a presença de
agentes patogénicos. Por esta razão, e considerando a importância do
uso sustentável dos recursos hídricos, as atuais normas e legislação
necessitam de uma revisão que garanta a salvaguarda da saúde pública,
em particular no contexto de utilização de água residual tratada. Neste
estudo foi desenvolvida uma metodologia para a preparação de amostras
e extração de RNA para a pesquisa e quantificação de vírus entéricos
- norovírus (NoV) genogrupos I (GI) e II (GII) e vírus da Hepatite
A, através de RT-PCR quantitativo em tempo real, além de terem sido
avaliados alguns dos tradicionais indicadores microbiológicos. Foram
colhidas e analisadas amostras de água naturais (superficiais e subterrâneas)
e de consumo; e águas residuais em três fases distintas de
tratamento – afluente bruto não tratado, efluente com tratamento secundário
por lamas ativadas e efluente sujeito a tratamento terciário por filtração
com areias e exposição a radiação ultravioleta (UV). O trabalho
desenvolvido permitiu detetar e quantificar os vírus entéricos em estudo
e ainda demonstrar que a ausência de FIB não implica a ausência de
microrganismos patogénicos, nomeadamente NoV GI e GII em águas
residuais sujeitas a tratamento terciário nas ETAR. Os resultados obtidos
indicam assim que podem persistir riscos para a saúde pública na
utilização de águas residuais tratadas, mesmo com tratamento terciário
como a utilização de UV.
Water is essential for life. It is therefore mandator y to protect it and to ensure its availability and quality for its dif ferent purposes. From a microbiological perspective, water quality assessment and monitoring are usually carried out using fecal contamination indicator bacteria (FIB) such as Escherichia coli or Enterococcus spp., acting as indicators for pathogen presence. However, the occurrence of these indicators is not always correlated with the presence of pathogens. For this reason and considering the impor tance of the sustainable use of water resources, current norms and legislation need to be revised to ensure the safeguard of public health, par ticularly in the context of the use of treated wastewater. In this study, a methodology was developed for sample preparation and RNA extraction for the search and quantification of enteric viruses – Norovirus (NoV) genogroups I (GI) and II (GII) and Hepatitis A virus, using real-time quantitative RT-PCR, in addition to evaluating some of the traditional microbiological indicators. Samples of natural and drinking waters were collected and analyzed; and also, wastewater at three dif ferent treatment stages – raw untreated influent, ef fluent with secondar y treatment by activated sludge and ef fluent subjected to ter tiar y treatment by sand filtration and ultraviolet radiation (UV) exposure. The work developed allowed to detect and quantify the enteric viruses under study and to demonstrate that the absence of FIB does not imply the absence of pathogenic microorganisms, namely NoV GI and GII in wastewater subjected to ter tiar y treatment in the WWTP. The results obtained thus indicate that risks to public health may persist with the use of treated wastewater, even with ter tiar y treatment such as the use of UV.
Water is essential for life. It is therefore mandator y to protect it and to ensure its availability and quality for its dif ferent purposes. From a microbiological perspective, water quality assessment and monitoring are usually carried out using fecal contamination indicator bacteria (FIB) such as Escherichia coli or Enterococcus spp., acting as indicators for pathogen presence. However, the occurrence of these indicators is not always correlated with the presence of pathogens. For this reason and considering the impor tance of the sustainable use of water resources, current norms and legislation need to be revised to ensure the safeguard of public health, par ticularly in the context of the use of treated wastewater. In this study, a methodology was developed for sample preparation and RNA extraction for the search and quantification of enteric viruses – Norovirus (NoV) genogroups I (GI) and II (GII) and Hepatitis A virus, using real-time quantitative RT-PCR, in addition to evaluating some of the traditional microbiological indicators. Samples of natural and drinking waters were collected and analyzed; and also, wastewater at three dif ferent treatment stages – raw untreated influent, ef fluent with secondar y treatment by activated sludge and ef fluent subjected to ter tiar y treatment by sand filtration and ultraviolet radiation (UV) exposure. The work developed allowed to detect and quantify the enteric viruses under study and to demonstrate that the absence of FIB does not imply the absence of pathogenic microorganisms, namely NoV GI and GII in wastewater subjected to ter tiar y treatment in the WWTP. The results obtained thus indicate that risks to public health may persist with the use of treated wastewater, even with ter tiar y treatment such as the use of UV.
Description
Keywords
Vírus Entéricos Norovírus Águas Superficiais Águas Subterrâneas Águas de Consumo Águas Residuais Água e Solo Saúde Pública Portugal
Pedagogical Context
Citation
Boletim Epidemiológico Observações. 2021 mai-ago;10(30):19-23
Publisher
Instituto Nacional de Saúde Doutor Ricardo Jorge, IP