Hepatitis E virus (HEV) is a non-enveloped single-stranded positive-sense RNA virus, belonging to the Hepeviridae family, resistant to environmental conditions, and transmitted by the consumption of contaminated water. This virus is responsible for both sporadic and epidemic outbreaks, leading to thousands of infections per year in several countries, and is thus considered an emerging disease in Europe and Asia. This study refers to a survey in Portugal during 2019, targeting the detection and eventual quantification of enteric viruses in samples from surface and drinking water. Samples positive for HEV RNA were recurrently found by reverse transcription quantitative PCR (RT-qPCR), in both types of matrix. The infectivity of these samples was evaluated in cultured Vero E6 cells and RNA from putative viruses produced in cultures evidencing cytopathic effects and was subjected to RT-qPCR targeting HEV genomic RNA. Our results evidenced the existence of samples positive either for HEV RNA (77.8% in surface water and 66.7% in drinking water) or for infectious HEV (23.0% in surface water and 27.7% in drinking water). These results highlight the need for effective virological control of water for human consumption and activities.
Monitoring the quality of water is a requisite to prevent outbreaks related to waterborne diseases, predominantly caused by pathogens like enteric viruses, usually transmitted via the fecal-oral route. This study aimed to survey a group of enteric viruses (Enterovirus, Norovirus genogroups I and II, and hepatitis A virus) in two surface water sources of drinking water, also intending to evaluate the extent of their elimination in the two water treatment plants (WTPs) involved in drinking water production. Correlations between these viruses and fecal indicator bacteria (FIB) were also evaluated. Positive samples for viral RNA were recurrently found by reverse transcription quantitative PCR (RT-qPCR) and quantified, in genomic copies per liter (gc/L) of sampled water. Viral RNAs were detected in 14 out of 27 samples of surface water, and 21 out of 36 samples of drinking water, NoV II having been the most frequently detected in both (0–78.6 gc/L and 0–12.5 gc/L, respectively). Both WTPs showed variable efficacies in the elimination of viral RNA. Only one correlation was found with FIB, between NoV II and intestinal enterococci. These results recommend the monitoring of enteric viruses over time and their inclusion in the mandatory analysis of water quality.
This paper presents the design features of a dynamic security assessment (DSA) system. The main issues regarding DSA system functionalities, security assessment methodologies, numerical algorithms, technical specification, and system architecture are discussed. Performance results of the real-time static security assessment are presented.Index Terms--dynamic security assessment, high performance computing, distributed processing system. 7 X. BIOGRAPHIES . He worked for a consulting (Themag) and a utility (Furnas Centrais Eletricas) company and for a research center (CEPEL) in Brazil. He worked also for a utility company (BCHydro) in Canada. At present he is a consultant for ONS, Operador Nacional do Sistema (Brazilian ISO). He is a member of IEEE. He has worked with power systems applications development and studies in planning and operation areas. Wes T. Kwasnicki (M'85) received his M.Sc. degree in Applied Mathematics from the Wroclaw University of Technology, Poland in 1979. He also received the M.Sc. and Ph.D. degrees in Electrical and Computer Engineering from the University of Manitoba, Canada in 1986 and 1998 respectively. He has worked for the Manitoba HVDC Research Centre (Winnipeg, Canada) between 1986 and 1999 where he was engaged in studies of various aspects of power systems, power electronics, applications of artificial intelligence, and development of electromagnetic transients simulation and high speed transient stability programs. At present he is a Senior Engineer with the British Columbia Transmission Corporation (Vancouver, Canada). He is a member of IEEE and a registered Professional Engineer in the Province of British Columbia.
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