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Microbiological Quality of Environmental Samples
Published in Maria Csuros, Csaba Csuros, Klara Ver, Microbiological Examination of Water and Wastewater, 2018
Maria Csuros, Csaba Csuros, Klara Ver
A number of viruses, such as the polioviruses, echoviruses, and coxsackieviruses, are transmitted by the feces-oral route. About 90 percent of viral gastroenteritis are caused by the rotavirus (named after its wheel shape, rota means wheel) or by the Norwalk agent (named after the outbreak in Norwalk, OH, in 1968). The symptoms are nausea, diarrhea, and vomiting with a low fever for a few days.
Use of ozonation technology to combat viruses and bacteria in aquatic environments: problems and application perspectives for SARS-CoV-2
Published in Environmental Technology, 2023
Letícia Reggiane de Carvalho Costa, Liliana Amaral Féris
Wang et al., [34] demonstrated the antiviral properties of gaseous ozone by testing 21 different viruses (mainly human pathogens), representing different virus families and structural features, in conventionally treated and ozone-treated sewage and sewage. All viruses tested were reduced to undetectable levels through ozonation, suggesting that they are possibly susceptible to the gas, and that this is a promising technique for decreasing transmission of many pathogenic human viruses. In the same way, Sigmon et al., [35] obtained, through ozonization, an inactivation of some human pathogenic viruses (poliovirus 1, echovirus 11, coxsackievirus B5 and adenovirus 2) and of several substitutes (Escherichia coli, coliphage T1, T4, PRD-1, ΦX174, and MS2). The authors reported that inactivation of all viruses and surrogates studied was greater than 4 log at ozone Ct levels less than 1 (mg/L)-min.
Pathogen contamination of groundwater systems and health risks
Published in Critical Reviews in Environmental Science and Technology, 2023
Yiran Dong, Zhou Jiang, Yidan Hu, Yongguang Jiang, Lei Tong, Ying Yu, Jianmei Cheng, Yu He, Jianbo Shi, Yanxin Wang
In the saturated zones, the die-off rates of groundwater pathogens are controlled by the types of pathogens, environmental factors and microbial composition (Figure 2). Different inactivation rates exist between species, even for those affiliated to the same genera (Sidhu & Toze, 2012). Higher temperature significantly enhances the inactivation of groundwater pathogens (John & Rose, 2005), while the impacts by dissolved oxygen (DO) are case-dependent. A slight decrease in inactivation was reported for bacteriophage MS2 and E. coli in anaerobic water than that in aerobic water, but significantly higher persistence under anoxic conditions was reported for Poliovirus and Coxsackievirus. This observation may be associated with the inhibited predatory eukaryotes or antagonistic bacteria under low DO conditions (Gordon & Toze, 2003). The mineral phase in the subsurface solid matrix also allows differential distribution of pathogens, whose inactivation may be influenced by strong electrostatic attractions between virus particles and charged surface, and denaturation of the pathogenesis-related proteins. Finally, the presence and activity of coexisting nonpathogenic microorganisms may also negatively impact the survival of the introduced pathogens via enzymatic attacks (Banning et al., 2002).
Evaluation of Human Norovirus Genogroup-II (HNoV-II) Inactivation by Ozonated Water Using Quantitative PCR Combined with PMA Pretreatment
Published in Ozone: Science & Engineering, 2021
Masahiro Otaki, Shinobu Kazama
The plaque assay revealed reduced concentrations of MS2, indicating its inactivation to below the detection limit in both solvents (Figure 1a). In contrast, qPCR and PMA + qPCR results showed a significant difference before heating in the case of MS2, shown in Figure 1a, b. It means that PMA could penetrate the MS2 capsid and inhibit the subsequent qPCR to 103~4 times lower in both solvents. Kim and Ko (2012) described that a higher concentration of PMA (>125 μM) inhibited the PCR detection of MS2 and confirmed that 10 μM PMA had no effect on PCR. In our experiments, PCR inhibition occurred when 50 μM PMA was used to achieve the same conditions as HNoV-II. According to Fittipaldi et al. (2010), DNA in coliphage T4 was detected at similar levels in qPCR and 100 μM PMA combined with qPCR, in PBS, before heating; which that meant PMA could not penetrate coliphage T4 capsid before heating. The DNA detected using PMA + qPCR was reduced with the heating step, but not by qPCR without PMA. Randazzo et al. (2017) applied PMA treatment at 50 μM concentration to HAV whose nucleic acid (ssRNA) is similar to MS2 and HNoV. Consequently, it was considered that the capsid of MS2 was relatively vulnerable to PMA penetration, compared with other viruses. In the case of MS2, RNA detection by qPCR without PMA pretreatment was decreased in sterilized tap water. It was concluded that PMA pretreatment combined with qPCR was difficult to apply to MS2 for estimating capsid damage, in sterilized tap water or PBS, when 50 μM PMA was used. In contrast, for HNoV-II, there was no significant difference in detection by qPCR and PMA + qPCR, before heating. However, we observed a significant difference in the results of qPCR and PMA + qPCR, in PBS, after heating, as shown in Figure 1d. It indicated that the capsid of HNoV-II could have been damaged by heating, thus leading to the penetration of PMA and subsequent inhibition of the qPCR. This result corresponds to previous studies for other enteric viruses such as coxsackievirus, poliovirus, echovirus, and Norwalk virus (Parshionikar, Laseke, and Fout 2010). In contrast, we observed significant a difference between qPCR without PMA pretreatment, before and after heating, in MS2 and HNoV-II, indicating that qPCR was inhibited by heating in sterilized tap water (shown in Figure 1a, c). It was assumed that the sterilized tap water contains some ions which has the potential to hydrolyze RNA, like of RNAse does, and it was accelerated by heating. Hypochlorous acid and the hypochlorite ion in sterile tap water were removed before the experiment. Thus, we assumed that other ions in the tap water inhibited qPCR, though it remains unclear what they are.