Comparison of methods for rotavirus detection in water and results of a survey of Jerusalem wastewater

Prospects and challenges of using electrochemical immunosensors as an alternative detection method for SARS-CoV-2 wastewater-based epidemiology

Given its potential applications in confronting the COVID-19 pandemic, wastewater-based epidemiology (WBE) has attracted tremendous attention. Developing a fast, cost-effective, and practical method for SARS-CoV-2 detection in wastewater is of great significance to facilitate future WBE development. By now, the PCR-based approach serves as the reference method and “gold standard” to detect the virus in wastewater. However, we found a trend that the PCR-based method becomes almost an unshakable choice as more and more studies were published regarding SARS-CoV-2 WBE. Of note, the importance of exploring new, alternative approaches for SARS-CoV-2 detection in wastewater should not be underestimated. In this context, the prospect of using electrochemical immunosensors as the alternative detection method was investigated in this survey. Based on the previous efforts towards different virus immunoassay studies and newly published PCR-based COVD-19 WBE works, this survey provides new insights into the electrochemical immunoassay that have been widely adopted in body fluids virus detection, along with an extensive discussion of the detection mechanism, detection performance, past performances, current efforts, and potential challenges with wastewater detection. In the end, this survey concludes that using electrochemical immunosensors to analyze SARS-CoV-2 in wastewater samples quantitatively may have better feasibility and practicability than using the conventional PCR-based approach, especially when considering its fast detection, ease of miniaturization, and potential on-site measurement.

Recent advances in biosensors for detecting viruses in water and wastewater

As there is a considerable number of virus particles in wastewater which cause numerous infectious diseases, it is necessary to eliminate viruses from domestic wastewater before it is released in the environment. In addition, on-site detection of viruses in wastewater can provide information on possible virus exposures in the community of a given wastewater catchment. For this purpose, the pre-detection of different strains of viruses in wastewaters is an essential environmental step. Epidemiological studies illustrate that viruses are the most challenging pathogens to be detected in water samples because of their nano sizes, discrete distribution, and low infective doses. Over the past decades, several methods have been applied for the detection of waterborne viruses which include polymerase chain reaction-based methods (PCR), enzyme-linked immunosorbent assay (ELISA), and nucleic acid sequence-based amplification (NASBA). Although they have shown acceptable performance in virus measurements, their drawbacks such as complicated and time-consuming procedures, low sensitivity, and high analytical cost call for alternatives. Although biosensors are still in an early stage for practical applications, they have shown great potential to become an alternative means for virus detection in water and wastewater. This comprehensive review addresses the different types of viruses found in water and the recent development of biosensors for detecting waterborne viruses.

Cellulose-based virus-retentive filters: a review

Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption-elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.

16 Methods for Detecting Microbial Pathogens in Food and Water

Newly developed methods for the detection of bacteria and viruses have provided microbiologists with the means to rapidly identify and monitor specific microorganisms in food and water. Traditional methods of testing involve culture techniques to increase the numbers of the organism to a detectable level, followed by isolation and biochemical identification. This chapter focuses on the methodologies to detect pathogens and indicator organisms; however, the methods described are applicable to most bacteria. As detection and isolation methods have improved, a growing number of pathogens have been identified as important food- and waterborne pathogens. This chapter describes the use of nucleic acid and antibody probes that have the potential to circumvent the need to culture the organism prior to identification. Nucleic acid probes have become a valuable diagnostic reagent in the identification of human and animal pathogens and have made possible the identification of viruses and bacteria that are difficult, if not impossible, to cultivate. DNA probes have also proved to be a useful tool for identifying and monitoring the organisms in food and the environment.

Proteolytic inactivation of simian-11 rotavirus: a pilot study

In an effort to develop alternate disinfectants for rotaviruses, pilot studies were conducted to determine if bacterial proteases could render simian-11 (SA-11) rotavirus non-infectious. SA-11 was found to be fairly temperature resistant, retaining a low-level of infectivity following 65 degrees C treatment for 2h at pH 8.5. It also resisted pH 8.5-5 at 45 degrees C for 2h. Alcalase, an alkaline protease, was the most effective of the various proteases (alcalase, durazym, neutrase, and savinase) tested. To analyze specific parameters for alcalase, SA-11 virus (10(5.5) median tissue culture infective dose/ml original titer) was treated at pH 6, 25 and 15 degrees C (simulated field conditions), with 0.1 and 1.0% alcalase. At pH 6.0 and 15 degrees C, 0.1% alcalase reduced SA-11 titer by 0. 75 log in 24h, and by 1.25 log in 120h. At 25 degrees C and pH 6.0, 0.1% alcalase reduced the titer by 2.25 log after 24h, and by 2.75 log in 120h. At pH 6.0 and 15 degrees C, 1% alcalase reduced SA-11 titer by 1.50 log in 24h and by 1.75 log in 120h. At the same enzyme concentration and pH, but at 25 degrees C the titer was reduced by 2. 75 log in the first 24h and by 3.25 log at 120h. These results show that the alkaline protease alcalase is capable of inactivating SA-11 virus to a certain degree depending on conditions. Further definition of operating parameters, demonstration of inactivation under field conditions and analysis whether the demonstrated degree of inactivation would decrease calf morbidity and mortality remain to be explored at this time.

Detecting Viruses in Water

Various and divergent approaches that have been used to concentrate and assay viruses from tap water and environmental freshwaters are summarized and briefly explained. The basic principles behind the different methodologies and descriptions of the most recent developments are emphasized. Comparisons help demonstrate the relative sensitivities of different concentration and assay techniques.