Methods to detect infectious human enteric viruses in environmental water samples
ABSTRACT Currently, a wide range of analytical methods is available for virus detection in environmental water samples. Molecular methods such as polymerase chain reaction (PCR) and quantitative real time PCR (qPCR) have the highest sensitivity and specificity to investigate virus contamination in water, so they are the most commonly used in environmental virology. Despite great sensitivity of PCR, the main limitation is the lack of the correlation between the detected viral genome and viral infectivity, which limits conclusions regarding the significance for public health. To provide information about the infectivity of the detected viruses, cultivation on animal cell culture is the gold standard. However, cell culture infectivity assays are laborious, time consuming and costly. Also, not all viruses are able to produce cytopathic effect and viruses such as human noroviruses have no available cell line for propagation. In this brief review, we present a summary and critical evaluation of different approaches that have been recently proposed to overcome limitations of the traditional cell culture assay and PCR assay such as integrated cell culture-PCR, detection of genome integrity, detection of capsid integrity, and measurement of oxidative damages on viral capsid protein. Techniques for rapid detection of infectious viruses such as fluorescence microscopy and automated flow cytometry have also been suggested to assess virus infectivity in water samples.
- SourceAvailable from: Sandra Martin-Latil
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- "Fruits and vegetables can be contaminated either at the pre-harvest stage through contact with fecally contaminated irrigation water or during harvesting, packaging, processing, or cooking due to poor hand sanitation (Bitler et al., 2013; Kotwal and Cannon, 2014; Mathijs et al., 2012; Rodriguez-Lazaro et al., 2012). Most foodborne viruses are difficult or currently impossible to cultivate (Hamza et al., 2011) and sensitive molecular methods are therefore used to detect them in food and environmental samples. Today, RTqPCR is widely used for virus detection because it is sensitive, specific, rapid and can deliver quantitative data. "
ABSTRACT: Noroviruses (genogroup I (NoV GI) and genogroup II (NoV GII)) and the hepatitis A virus (HAV) are frequently involved in foodborne infections worldwide. They are mainly transmitted via the fecal-oral route, direct person-to-person contact or consumption of contaminated water and foods. In food virology, detection methods are currently based on identifying viral genomes using real-time reverse transcriptase PCR (RT-qPCR). One of the general requirements for detecting these viruses in food involves the use of a process control virus to monitor the quality of the entire viral extraction procedure as described in the ISO/TS 15216-1 and 15216-2 standards published in 2013. The selected process control virus should have similar morphological and physicochemical properties as the screened pathogenic virus and thus have the potential to provide comparable extraction efficiency. The aim of this study was to determine which virus should be used for process control, murine norovirus (MNV-1) or Mengovirus, when testing for the presence of HAV, NoV GI and NoV GII in bottled water, lettuce and semi-dried tomatoes. Food samples were spiked with HAV, NoV GI or NoV GII alone or in the presence of MNV-1 or Mengovirus. Recovery rates of each pathogenic virus were compared to those of both process control viruses using a multiple comparison procedure. Neither process control virus influenced the recovery of pathogenic virus regardless of the type of food matrix. MNV-1 was the most appropriate virus for validating the detection of HAV and NoV GII in all three food matrices as well as NoV GI in lettuce. Mengovirus proved to be the most appropriate control for NoV GI detection in bottled water and semi-dried tomatoes. The process control virus is essential for validating viral detection in food and the choice of virus depends on food type and the screened pathogenic virus. Copyright © 2015 Elsevier B.V. All rights reserved.International Journal of Food Microbiology 02/2015; 202:57-65. DOI:10.1016/j.ijfoodmicro.2015.02.029 · 3.16 Impact Factor
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- "identified by propagating the virus in a cellular model, to discriminate between infectious and non-infectious particles. Some studies have shown that evaluation of the integrity of viral capsid , by pre-treatment of water samples with DNA intercalating dyes (Fittipaldi et al., 2010; Parshionikar et al., 2010; Bae and Wuertz, 2012) or by nuclease pre-digestion (Nuanualsuwan and Cliver, 2002; Seitz et al., 2011), can overcome the drawbacks (Hamza et al., 2011). Another limitation of molecular methods is the presence of naturally-occurring inhibitory compounds that are problematic during genome amplification-based analysis of environmental samples, particularly for large volumes of water samples (Hata et al., 2011). "
ABSTRACT: Despite the progress in water and wastewater treatment technologies, waterborne diseases are still a major concern of public health. In the reported water-related outbreaks, viruses constitute one of the main causal agents. Enteroviruses are one of the most viruses monitored in water and are often used as an indicator of viral pollution. Isolation and identification of this virus are now regularly based on molecular tools. However published or commercial protocols for detection of these viruses in water are frequently lacking of validation processes and performances evaluation in such complex samples. A method for enterovirus detection in environmental water has been developed, its performance has been evaluated and compared with several commercial kits. The sensitivity of commercial methods in clinical samples, ranged between 89% and 100%, while the sensitivity in seeded environmental matrices fell between 16% and 91%. This method showed the best performance in environmental samples and was subsequently applied on surface and treated wastewater. The results showed the large dissemination of enteroviruses in an urbanized river. The results also emphasized the importance of good knowledge of the method's limits for its utilization in environmental samples in order to minimize false negatives and to avoid underestimating viral concentration.Journal of Virological Methods 09/2014; 209. DOI:10.1016/j.jviromet.2014.08.016 · 1.88 Impact Factor
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- "The detection of TTV DNA in water samples may indicate the presence of other enteric viruses and fecal contaminants (Ahmed et al. 2009; Hamza et al. 2011). In the present study, the most populated municipalities, Caxias do Sul and Pelotas, treated their sewage very poorly at the time of sampling. "
ABSTRACT: Torque teno virus (TTV) was surveyed in tap water collected in schools from three municipalities located in the south of Brazil. TTV genomes were found in 11.7 % (4/34) of the samples. TTV DNA was detected in 10.5 % (2/19) of the samples collected at the city of Caxias do Sul and in 25 % (2/8) of the samples from Pelotas. Those cities have a low rate of sewage treatment. All samples from Santa Cruz do Sul, which has nearly 92 % of its sewage treated, were negative. These results suggest that the amount of sewage treated may have an effect on the detection rates of TTV DNA in drinking water in a given urban area, showing a mild negative correlation (r = -0.76), when comparing the percentage of sewage treatment to the detection of TTV genomes. The detection rate of TTV was also compared with Escherichia coli, showing a strong correlation (r = 0.97), indicating that TTV may be a suitable marker of fecal contamination.Food and Environmental Virology 03/2013; 5(1):41-5. DOI:10.1007/s12560-012-9096-7 · 1.98 Impact Factor