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In the field of chemical engineering and water treatment, the study of viruses, included surrogates, is well documented. Often, surrogates are used to study viruses and their behavior because they can be produced in larger quantities in safer conditions and are easier to handle. In fact, surrogates allow studying microorganisms which are non-infectious to humans but share some properties similar to pathogenic viruses: structure, composition, morphology, and size. Human noroviruses, recognized as the leading cause of epidemics and sporadic cases of gastroenteritis across all age groups, may be mimicked by the Tulane virus. The objectives of this work were to study (i) the ultrafiltration of Tulane virus and norovirus to validate that Tulane virus can be used as a surrogate for norovirus in water treatment process and (ii) the retention of norovirus and the surrogate as a function of water quality to better understand the use of the latter pathogenic viruses. Ultrafiltration tests showed significant logarithmic reduction values (LRV) in viral RNA: around 2.5 for global LRV (i.e., based on the initial and permeate average concentrations) and between 2 and 6 for average LRV (i.e., retention rate considering the increase of viral concentration in the retentate), both for norovirus and the surrogate Tulane virus. Higher reduction rates (from 2 to 6 log genome copies) are obtained for higher initial concentrations (from 101 to 107 genome copies per mL) due to virus aggregation in membrane lumen. Tulane virus appears to be a good surrogate for norovirus retention by membrane processes. [ABSTRACT FROM AUTHOR]

Coastal areas are frequently contaminated by microorganisms of human origin, due to high population density and low seawater renewal. To evaluate the impact of wastewater input on shellfish quality, a study was conducted in Brittany (France) over a period of 20 months. A hydrodynamic model was used to simulate wastewater impact on microbial water quality. To validate the model, wastewater from the three main sewage treatment plants and shellfish from three sites were sampled monthly. Bacterial indicators (E. coli), F-RNA phages were searched for by culture and noroviruses by RT-PCR and hybridisation. These microorganisms were detected in the three effluents and clams, with no marked seasonal variation. The microbial concentrations in the two oyster beds, distant from the effluent outfall, were low, and only three of the samples were positive for norovirus. For simulation, the winter wastewater inputs of E. coli and phages were calculated and an estimation for norovirus flux was made from the epidemic situation in the population. The microbial behaviour was included in the model by a decay-rate factor. Results from the model calculations were found to be very similar to E. coli and phage concentrations observed in shellfish. For noroviruses, the model indicated that shellfish distant from the wastewater input were under the detection limit of the RT-PCR method. This study demonstrated the use of modelisation to interpret norovirus contamination in various areas. [ABSTRACT FROM AUTHOR]

Evaluates a few procedures for the detection of astroviruses in wastewater samples. Investigation of the occurrence of astroviruses in wastewater samples from three different sewage treatments plants located in Southern France and two in the Barcelona area; How the amplimers generated contain several sites for the DdeI restriction endonuclease.

Describes how an outbreak of hepatitis A, affecting 183 people, occurred in Valencia, Spain. How epidemiological evidence pointed to an association of the outbreak with consumption of Coquina clams, imported frozen from Peru; Analyzation of the shellfish for the presence of hepatitis A virus, enteroviruses, rotaviruses, astroviruses, caliciviruses and hepatitis E virus.

Examines the detection of the main pathogenic enteric viruses able to persist in the environment such as hepatitis A virus (HAV), Norwalk-like virus (NLV), enterovirus, rotavirus and astrovirus via reverse transcription-PCR and hybridization in shellfish. Contamination of oyster samples; Variety of strains in HAV and NLV amplicons; Viral contamination during winter months.

Focuses on the detection of Rotavirus double-stranded RNA in sewage by the reverse transcriptase seminested polymerase chain reaction (PCR) and restriction fragment length polymorphism assay. Demonstration of the presence of naturally occurring rotaviruses; Analysis of the amplified viral sequences; Restriction profiles; Identical viral sequences detected.

Reports on the polymerase chain reaction evaluation of viral contamination in five shellfish beds over a 21-month period. Viral extraction performed on dissected tissues and clinically most important enteric viruses; Two sites regularly contaminated by fecal coliforms with the highest percentage of viral contamination.

We constructed an internal control based on the poliovims genome and cloned it into a transcription plasmid to obtain a competitor RNA distinguishable by its size from the wild-type PCR product. A known number of copies was introduced into sewage samples before nucleic acid extraction in order to evaluate the reliability of the extraction step and amplification. The final gel was analysed with a densitometer and the number of viral RNA copies present in the sewage was calculated. In vitro experiments were carried out with this internal control with peracetic acid and UV to estimate decontamination efficiency. A very high concentration of peracetic acid was required to eliminate viruses with a moderate UV dose to obtain a negative PCR. This study demonstrates that competitor RNA is useful both in controlling the different reaction steps (extraction and amplification) and inhibitor detection and in providing a quantitative estimation of contamination. [ABSTRACT FROM AUTHOR]