Article

Inactivation of human and simian Rotaviruses by chlorine dioxide

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Abstract

The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4 degrees C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10(5)-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate at neutral pH, and the sensitivities to chlorine dioxide were similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants.

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... The different functional groups on the outer surface of enveloped viruses compared to nonenveloped viruses likely impact their survival and partitioning behavior in aqueous environments (Arbely et al. 2006;Gundy et al. 2009;Shigematsu et al. 2014). Many factors have been found to exert great impacts on virus inactivation rates such as ClO 2 dosage, pH, and temperature (Berman and Hoff 1984;Chen and Vaughn 1990;Hornstra et al. 2011;Thurston-Enriquez et al. 2005). The mechanisms of inactivation of virus by ClO 2 include the disruption of the virus protein or the damage of genome (Jin et al. 2013(Jin et al. ,2012Li et al. 2004;Sigstam et al. 2013;Wigginton et al. 2012). ...
... The inactivation of bacteriophage f2 increases by more than 5 log after treatment with ClO 2 for 2 min when pH increases from 5.0 to 9.0 (Taylor and Butler 1982). Enhanced inactivation with increasing pH is also observed in adenovirus type 40 (Thurston-Enriquez et al. 2005), feline calicivirus (Chen and Vaughn 1990) and simian rotavirus SA11 (Berman and Hoff 1984;Chen and Vaughn 1990). Unlike dose effect, pH does not affect the initial inactivation phase so strongly, but seems to have an effect on the tailing phase. ...
... The inactivation of bacteriophage f2 increases by more than 5 log after treatment with ClO 2 for 2 min when pH increases from 5.0 to 9.0 (Taylor and Butler 1982). Enhanced inactivation with increasing pH is also observed in adenovirus type 40 (Thurston-Enriquez et al. 2005), feline calicivirus (Chen and Vaughn 1990) and simian rotavirus SA11 (Berman and Hoff 1984;Chen and Vaughn 1990). Unlike dose effect, pH does not affect the initial inactivation phase so strongly, but seems to have an effect on the tailing phase. ...
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Chlorine dioxide (ClO2), an alternative disinfectant to chlorine, has been widely applied in water and wastewater disinfection. This paper aims at presenting an overview of the inactivation kinetics and mechanisms of ClO2 with viruses. The inactivation efficiencies vary greatly among different virus species. The inactivation rates for different serotypes within a family of viruses can differ by over 284%. Generally, to achieve a 4-log removal, the exposure doses, also being referred to as Ct values (mutiplying the concentration of ClO2 and contact time) vary in the range of 0.06–10 mg L−1 min. Inactivation kinetics of viruses show two phases: an initial rapid inactivation phase followed by a tailing phase. Inactivation rates of viruses increase as pH or temperature increases, but show different trends with increasing concentrations of dissolved organic matter (DOM). Both damages in viral proteins and in the 5′ noncoding region within the genome contribute to virus inactivation upon ClO2 disinfection.
... The predictive curves of which the m-value did not take the appropriate range are shown as dashed lines in Figure 4. In the first dataset of poliovirus, until 3 min, test datasets did not deviate from the predictive curve (Figure 4a; 0.29 ppm of free chlorine, k' = 0.001 (min −1 ), pH = 7.0, temperature = 26.5 • C, infectivity and purified water [47]), whereas the second dataset were in the range of prediction after 1.5 min of contact time (Figure 4b; 0.49 ppm of free chlorine, k' = 0.001 (min −1 ), pH = 7.8, temperature = 5.0 • C, infectivity and purified water [28]). The test data of adenoviruses gathered near the 50% predictive curve (Figure 4c; 5.4 ppm of free chlorine, k' = 3.13 (min −1 ), pH = 8.0, temperature = 25 • C, infectivity and purified water [24]). ...
... The predictive curve of hepatitis A virus converged to about −1.3, and test data were on the predictive curve except for a value of inactivation efficiency at 2 min (Figure 4d; 0.5 ppm of free chlorine, k' = 1.17 (min −1 ), pH = 6.0, temperature = 5.0 • C, infectivity and purified water [37]). The predictive curves of coxsackievirus displayed a weaker tailing, so that the range of the predictive curve widened as time went on (Figure 4e; 0.25 ppm of free chlorine, k' = 0.07 (min −1 ), pH = 10, temperature = 26.5 • C, infectivity and purified water [47]). The test data of coxsackievirus were placed from 25% to 50% predictive curves. ...
... The predictive curves of which the m-value did not take the appropriate range are shown as dashed lines in Figure 4. In the first dataset of poliovirus, until 3 min, test datasets did not deviate from the predictive curve ( Figure 4a; 0.29 ppm of free chlorine, k' = 0.001 [min −1 ], pH = 7.0, temperature = 26.5 °C, infectivity and purified water [47]), whereas the second dataset were in the range of prediction after 1.5 min of contact time (Figure 4b; 0.49 ppm of free chlorine, k' = 0.001 [min −1 ], pH = 7.8, temperature = 5.0 °C, infectivity and purified water [28]). The test data of adenoviruses gathered near the 50% predictive curve (Figure 4c; 5.4 ppm of free chlorine, k' = 3.13 [min −1 ], pH = 8.0, temperature = 25 °C, infectivity and purified water [24]). ...
Article
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Hazard analysis and critical control point (HACCP) are a series of actions to be taken to ensure product consumption safety. In food poisoning risk management, researchers in the field of predictive microbiology calculate the values that provide minimum stress (e.g., temperature and contact time in heating) for sufficient microbe inactivation based on mathematical models. HACCP has also been employed for health risk management in sanitation safety planning (SSP), but the application of predictive microbiology to water-related pathogens is difficult because the variety of pathogen types and the complex composition of the wastewater matrix does not allow us to make a simple mathematical model to predict inactivation efficiency. In this study, we performed a systematic review and meta-analysis to construct predictive inactivation curves using free chlorine for enteric viruses based on a hierarchical Bayesian model using parameters such as water quality. Our model considered uncertainty among virus disinfection tests and difference in genotype-dependent sensitivity of a virus to disinfectant. The proposed model makes it possible to identify critical disinfection stress capable of reducing virus concentration that is below the tolerable concentration to ensure human health.
... Viral inactivation by oxidative agents such as chlorine (Engelbrecht et al. 1980;Berman and Hoff 1984), chloramine (Berman and Hoff 1984;Shin and Sobsey 1998), chlorine dioxide (ClO 2 ) (Alvarez and O'Brien 1982b;Berman and Hoff 1984) or ozone (Herbold et al. 1989;Finch and Fairbairn 1991) is widely described in the literature. Studies devoted to viral inactivation have essentially focused on defining disinfection conditions for each oxidant, using the cell culture as the sole measure of effectiveness (Scarpino et al. 1979;Engelbrecht et al. 1980;Sharp et al. 1980;Berman and Hoff 1984;Chen and Vaughn 1990). Nevertheless, it is impossible with such a method to define whether the oxidants target the viral capsid (i.e. ...
... Finally, the virus completely lost its infectivity after 3 min of exposure to 5 mg l )1 of ClO 2 . This finding is in good agreement with data in the literature considering the dose of ClO 2 used (Alvarez and O'Brien 1982b;Berman and Hoff 1984;Noss et al. 1986;Chen and Vaughn 1990). After 15 min, the drop-off was >4AE5 log (quantification threshold) for the infectious virus, >3AE5 log (detection threshold) for the most sensitive native RNA fragment, 5¢-UTRdT, and 1AE4 log for the most resistant native RNA fragment, 3C. ...
Article
This study was undertaken to gain an understanding of the factors that influence viral RNA degradation in the presence of chlorine dioxide (ClO(2)), which will be very useful in helping to define the significance of the presence of the viral genome in disinfected water. We focused our investigation on the influence of ClO(2) on extracted RNA on the one hand, and on the infectious virus on the other. Our first results show that RNA degradation, like viral inactivation, is dose dependent. The influence of the spatial organization of the targeted genomic sequence, as well as that of its size and location (and/or sequence) on degradation of the Poliovirus 1 genome by ClO(2), was studied using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The results show that the preferential sites of action of ClO(2) appear to be located in the untranslated regions, 5'- and 3'-UTR, a phenomenon influenced by both the presence of secondary structures and the genomic sequence in these regions. Our results also reveal a rapid decrease of infectious particles quantified by the cell culture for the applied dose. Comparison between cell culture and real-time PCR for viral detection reveals disagreement following disinfection treatment, even for the largest targeted fragment (a 6,989-base fragment representing the quasi-whole viral genome). The detection of genome fragments is insufficient to confirm the presence of the infectious virus, as each targeted fragment shows a different sensitivity. Hence, the smallest targeted fragment (76 bp) persisted throughout the analysis period, while the longest targeted fragment (6,989 bp) disappeared very rapidly. Highly sensitive regions (i.e. 5'- and 3'-UTR) should be targeted to avoid an overestimation of the risk of viral infection using molecular biology methods in water following disinfection. Further studies in this area are needed. To date, it has not been possible to routinely apply virological controls to drinking water because of the time-consuming nature of the gold standard technique (cell culture) and its inability to detect all serotypes (e.g. Norovirus). Molecular techniques (e.g. real-time RT-PCR) constitute a solution to the rapid and specific detection of all the serotypes. However, ignorance of the mechanisms of viral degradation prevents the validation of PCR for the measurement of the risk of infection to humans following disinfection treatment.
... Previously, it was reported that different viruses have different susceptibilities to ClO 2 gas (33)(34)(35)(36). A systematic study compared the efficacy of ClO 2 and sodium hypochlorite solutions against several viruses, including FCV, human influenza virus, measles virus, canine distemper virus, human herpesvirus, human adenovirus, canine adenovirus, and canine parvovirus (33). ...
... A 3-log reduction in simian rotavirus SA-11 was achieved following treatment with the 0.2-mg/liter ClO 2 solution after 60 s. However, in order to achieve the same log re-duction in human rotavirus strain Wa, the treatment time needed to be increased to 120 s (36). There also remains the possibility that viral quasispecies from the same viral population may have more resistance to ClO 2 treatment than the rest of the population or that aggregation of viral particles may protect a subset of the viral population from ClO 2 inactivation. ...
Article
Acute gastroenteritis caused by human norovirus is a significant public health issue. Fresh produce and seafood are examples of high-risk foods associated with norovirus outbreaks. Food contact surfaces also have the potential to harbor noroviruses if exposed to fecal contamination, aerosolized vomitus, or infected food handlers. Currently, there is no effective measure to decontaminate norovirus on food contact surfaces. Chlorine dioxide (ClO2) gas is a strong oxidizer and is used as a decontaminating agent in food processing plants. The objective of this study was to determine the kinetics and mechanism of ClO2 gas inactivation of a norovirus surrogate, murine norovirus 1 (MNV-1), on stainless steel (SS) coupons. MNV-1 was inoculated on SS coupons at the concentration of 107 PFU/coupon. The samples were treated with ClO2 gas at 1, 1.5, 2, 2.5, and 4 mg/liter for up to 5 min at 25°C and a relative humidity of 85%, and virus survival was determined by plaque assay. Treatment of the SS coupons with ClO2 gas at 2 mg/liter for 5 min and 2.5 mg/liter for 2 min resulted in at least a 3-log reduction in MNV-1, while no infectious virus was recovered at a concentration of 4 mg/liter even within 1 min of treatment. Furthermore, it was found that the mechanism of ClO2 gas inactivation included degradation of viral protein, disruption of viral structure, and degradation of viral genomic RNA. In conclusion, treatment with ClO2 gas can serve as an effective method to inactivate a human norovirus surrogate on SS contact surfaces.
... Eosinophilic intranucleus inclusions and cytoplasmic inclusions in the epithelial cells of digestive tract (Sandhu and Metwally, 2008 and OIE Terrestrial-Manual, 2012). Chlorine dioxide (clo 2 ) is an effective bactericide ( Rice andGomez, 1986 andMaw, et al., 2008), sporicide (Maw, et al., 2008), algicide (Junil, et al., 1994, Junil, et al., 1997and Maw, et al., 2008, planktoncide (Chauret, et al., 2001 andMaw, et al., 2008) and virucide (Alvarez and Brien, 1982, Chen and Vaughn, 1990, Junil et al., 1997and Maw, et al., 2008, due to it's strong oxidation with the viral ribonucleic acid (Alvarez andBrien, 1982 andMaw, et al., 2008) or the other organic compounds of microorganism (Kim, et al., 1999). Clo 2 is considered to be a more effective bactericide and less formation of chlorinated organics than aqueous chlorine under a relatively wider range of PH conditions (Junil, et al., 1997, Kim, et al., 1999and Maw, et al., 2008. ...
... Also the microscopic findings of other organs in the present study showed moderate catarrhal enteritis with desquamation of the lining epithelium in both groups and activation of lymphocytes in spleen and bursa of the vaccinated group. The present microscopical lesions of the examined organs were reduced in the group of duck which received the chlorine dioxide (clo 2 ) solution disinfectant (sodium hypochlorite), these results indicated that the chlorine dioxide have a protective effect against viral infection when using at low concentration in the drinking water ( They concluded that there are many reports mentioned that chlorine dioxide solution has a virucidal activity (Alvarez and Brien 1982, Chen, 1990 and Takanori and Takashi 2010). On the same line (Norio and Takashi 2008 and Takanori and Takashi 2010) discussed the virucidalefficacy of chlorine dioxide gas, they concluded that clo 2 gas is effective at preventing aerosol-induced influenza virus infection in mice by denaturing viral envelope protein at a concentration well below the permissible exposure level to humans. ...
Article
Full-text available
The present study was directed to explore the efficacy of chlorine dioxide disinfectant when using at low concentration in drinking water to ameliorate the pathological alteration on ducks experimentally infected with Duck Virus Enteritis. Fifty Muscovy ducks were equally divided into 5 groups. Group 1was kept as negative control. Group 2 was administrated 3ppm sodium hypochlorite disinfectant solution in drinking water for 15 days, cleaning the objects and utensils with this disinfectant till the end of study. Groups 3,4 were infected at 30 day of age by1ml/duck intramuscular by organs suspension homogenate of Duck Virus Enteritis (DVE) previously prepared, group 4 was adminis-trated also 3ppm sodium hypochlorite disinfectant in drinking water for 15 days and cleaning the objects and utensils with this disinfectant till the end of study. Group 5 was vaccinated against Duck Virus Enteritis (DVE) at 15 day of age by local strain and infected at 30 day of age by 1ml/duck in-tramuscular from organs homogenate suspension of DVE previously prepared. Blood was collected weekly for immunological investigations. After the appearance of clinical signs of the disease and death occur, necropsy and tissue specimens were collected from the liver, intestine, esophagus, heart, kidneys, spleen and bursa of Fabricius and fixed in 10%buffered neutral formalin solution for histopathologically investigation and Immunohistochemical examination. The results of the experimentally infected group indicated the clinical signs of Duck Virus Enteritis. Microscopically the infected group showed congestion and hemorrhage in the blood vessel of most examined organs together with multiple areas of necrosis in liver and intestine together with eosinophilic and rarely ba-sophilic intranuclear inclusion bodies in the epithelial lining of the bile ducts, intestinal epithelium and in the covering cells of the esophagus. Depletion and necrosis in the lymphocytes of white pulp together with congestion and hemorrhage of red pulp of spleen. On the other hand, the groups which received chlorine dioxide disinfectant and the vaccinated group showed obvious improvements in the clinical signs and microscopical picture. Form these results it could be concluded that, chlorine dioxide solution disinfectant when using at low concentration ameliorate the pathological changes induced by the Duck Viral Enteritis infection.
... Eosinophilic intranucleus inclusions and cytoplasmic inclusions in the epithelial cells of digestive tract (Sandhu and Metwally, 2008 and OIE Terrestrial-Manual, 2012). Chlorine dioxide (clo 2 ) is an effective bactericide ( Rice andGomez, 1986 andMaw, et al., 2008), sporicide (Maw, et al., 2008), algicide (Junil, et al., 1994, Junil, et al., 1997and Maw, et al., 2008, planktoncide (Chauret, et al., 2001 andMaw, et al., 2008) and virucide (Alvarez and Brien, 1982, Chen and Vaughn, 1990, Junil et al., 1997and Maw, et al., 2008, due to it's strong oxidation with the viral ribonucleic acid (Alvarez andBrien, 1982 andMaw, et al., 2008) or the other organic compounds of microorganism (Kim, et al., 1999). Clo 2 is considered to be a more effective bactericide and less formation of chlorinated organics than aqueous chlorine under a relatively wider range of PH conditions (Junil, et al., 1997, Kim, et al., 1999and Maw, et al., 2008. ...
... Also the microscopic findings of other organs in the present study showed moderate catarrhal enteritis with desquamation of the lining epithelium in both groups and activation of lymphocytes in spleen and bursa of the vaccinated group. The present microscopical lesions of the examined organs were reduced in the group of duck which received the chlorine dioxide (clo 2 ) solution disinfectant (sodium hypochlorite), these results indicated that the chlorine dioxide have a protective effect against viral infection when using at low concentration in the drinking water ( They concluded that there are many reports mentioned that chlorine dioxide solution has a virucidal activity (Alvarez and Brien 1982, Chen, 1990 and Takanori and Takashi 2010). On the same line (Norio and Takashi 2008 and Takanori and Takashi 2010) discussed the virucidalefficacy of chlorine dioxide gas, they concluded that clo 2 gas is effective at preventing aerosol-induced influenza virus infection in mice by denaturing viral envelope protein at a concentration well below the permissible exposure level to humans. ...
Article
Full-text available
The present study was directed to explore the efficacy of chlorine dioxide disinfectant when using at low concentration in drinking water to ameliorate the pathological alteration on ducks experimentally infected with Duck Virus Enteritis. Fifty Muscovy ducks were equally divided into 5 groups. Group 1was kept as negative control. Group 2 was administrated 3ppm sodium hypochlorite disinfectant solution in drinking water for 15 days, cleaning the objects and utensils with this disinfectant till the end of study. Groups 3,4 were infected at 30 day of age by1ml/duck intramuscular by organs suspension homogenate of Duck Virus Enteritis (DVE) previously prepared, group 4 was adminis-trated also 3ppm sodium hypochlorite disinfectant in drinking water for 15 days and cleaning the objects and utensils with this disinfectant till the end of study. Group 5 was vaccinated against Duck Virus Enteritis (DVE) at 15 day of age by local strain and infected at 30 day of age by 1ml/duck in-tramuscular from organs homogenate suspension of DVE previously prepared. Blood was collected weekly for immunological investigations. After the appearance of clinical signs of the disease and death occur, necropsy and tissue specimens were collected from the liver, intestine, esophagus, heart, kidneys, spleen and bursa of Fabricius and fixed in 10%buffered neutral formalin solution for histopathologically investigation and Immunohistochemical examination. The results of the experimentally infected group indicated the clinical signs of Duck Virus Enteritis. Microscopically the infected group showed congestion and hemorrhage in the blood vessel of most examined organs together with multiple areas of necrosis in liver and intestine together with eosinophilic and rarely ba-sophilic intranuclear inclusion bodies in the epithelial lining of the bile ducts, intestinal epithelium and in the covering cells of the esophagus. Depletion and necrosis in the lymphocytes of white pulp together with congestion and hemorrhage of red pulp of spleen. On the other hand, the groups which received chlorine dioxide disinfectant and the vaccinated group showed obvious improvements in the clinical signs and microscopical picture. Form these results it could be concluded that, chlorine dioxide solution disinfectant when using at low concentration ameliorate the pathological changes induced by the Duck Viral Enteritis infection.
... The generation of gaseous chlorine dioxide (ClO 2 ) is one of several techniques available for the remediation of structures impacted by microbial growth (U.S. Environmental Protection Agency [EPA], 2007). ClO 2 can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans (Taylor and Butler, 1982;Chen and Vaughn, 1990;Sivaganesan et al., 2003;Loret et al., 2005). ClO 2 dissolves readily in water, forming a stable state of small particles. ...
Article
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Unlabelled: In Taiwan, the food and drink requirements of students and faculty members are met by student cafeterias. The air quality within these cafeterias should satisfy the guidelines laid down by the Taiwan Environmental Protection Agency (Taiwan EPA). Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (ClO2) treatments in disinfecting a local student cafeteria, namely a single, one-off application and a twice-daily application. In both cases, the ClO2 was applied using strategically placed aerosol devices. The air quality before and after disinfection was evaluated by measuring the bioaerosol levels of bacteria and fungi. Moreover, a stepwise discriminant analysis method was applied for predicting the residual concentrations of bacteria and fungi, as a function of the environmental parameters and the ClO2 concentration. The experimental results showed that the average background levels of bacteria and fungi prior to ClO2 disinfection were 972.5 +/- 623.6 and 1534.1 +/- 631.8 colony-forming units (CFU)/m3, respectively. A single ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 65% and 30%, respectively. By contrast, a twice-daily ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 74% and 38%, respectively. The statistical analysis results showed that the residual bacterial concentration level was determined primarily by the number of individuals present in the cafeteria, the temperature, and the ClO2 concentration, whereas the residual fungal concentration level was determined mainly by the temperature, the total number of suspended particles, and the ClO2 concentration. Thus, the integrated results suggest that the air quality guidelines prescribed by the Taiwan EPA for student cafeteria can best be achieved by applying ClO2 twice daily using an appropriate deployment of aerosol devices. Implications: ClO2 gas can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans, in indoor environments. Moreover, it is popularly known that bioaerosols are able to grow and propagate on a wide variety of building materials and indoor surfaces. Thus, through optimal ClO2 disinfection methodology, the indoor microbial contaminants can be decreased and the residual concentrations of bacteria and fungi as a function of the environmental parameters and the ClO2 concentration can be predicted via some statistical techniques.
... The generation of gaseous chlorine dioxide (ClO 2 ) is one of several techniques available for the remediation of structures impacted by microbial growth (US EPA 2007). ClO 2 can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans (Taylor and Butler 1982;Chen and Vaughn 1990;Sivaganesan et al. 2003;Loret et al. 2005). Furthermore, ClO 2 dissolves readily in water, forming a stable state of small particles. ...
Article
Full-text available
As with all indoor public spaces in Taiwan, the stack rooms in public libraries should meet the air quality guidelines laid down by the Taiwan Environmental Protection Administration. Accordingly, utilizing a university library in Taiwan for experimental purposes, this study investigates the efficiency of gaseous chlorine dioxide (ClO2) as a disinfection agent when applied using three different treatment modes, namely a single-daily disinfection mode (SIM), a twice-daily disinfection mode (TWM), and a triple-daily disinfection mode (TRM). For each treatment mode, the ClO2 is applied using an ultrasonic aerosol device and is performed both under natural lighting conditions and under artificial lighting conditions. The indoor air quality is evaluated before and after each treatment session by measuring the bioaerosol levels of bacteria and fungi. The results show that for all three disinfection modes, the application of ClO2 reduces the indoor bacteria and fungi concentrations to levels lower than those specified by the Taiwan EPA (i.e., bacteria <1500 CFU/m(3), fungi <1000 CFU/m(3)), irrespective of the lighting conditions under which the disinfection process is performed. For each disinfection mode, a better disinfection efficiency is obtained under natural lighting conditions since ClO2 readily decomposes under strong luminance levels. Among the three treatment modes, the disinfection efficiencies of the TWM and TRM modes are very similar under natural lighting conditions and are significantly better than that of the SIM mode. Thus, overall, the results suggest that the TWM treatment protocol represents the most cost-effective and efficient method for meeting the indoor air quality requirements of the Taiwan EPA.
... The generation of gaseous chlorine dioxide (ClO 2 ) is one of several techniques used for the remediation of structures impacted by microbial growth (US EPA 2007). ClO 2 can destroy all manners of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans (Taylor and Butler 1982;Chen and Vaughn 1990;Sivaganesan et al. 2003;Loret et al. 2005;Hsu and Huang 2013). Moreover, ClO 2 dissolves readily in water, forming a stable state of small particles. ...
Article
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Public elevators are an essential requirement in modern high-rise buildings. However, the confined, crowded interior of an elevator provides an ideal breeding ground for all manners of biological aerosols. Consequently, when using an elevator at a university in Taiwan as the research target, this study performs an experimental investigation into the effectiveness of hand-sprayed gaseous chlorine dioxide as a disinfection agent. The air quality before and after disinfection is evaluated by measuring the bioaerosol concentrations of bacteria and fungi, respectively. The average background levels of bacteria and fungi before disinfection are found to be 635.7 ± 469.6 and 1296.8 ± 966.6 colony-forming unit (CFU)/m(3), respectively. Following disinfection, the bacteria and fungi concentrations reduced by an average of 35 and 25 %, respectively. The multivariate analysis of variance (MANOVA) results showed that the residual bacteria and fungi concentration levels were determined primarily by the number of individuals within the elevator and the elapsed time following disinfection. In general, the present results show that given a maximum of five individuals within the elevator, a disinfection schedule of once every 40 min is sufficient to reduce the bioaerosol concentrations of bacteria and fungi to the levels specified by the Taiwan Environmental Protection Agency (EPA).
... At pH 8.2, the corresponding value was only 4.92 mg/L·min. These findings are in good agreement with other reports on inactivation of simian rotavirus SA11, coliphage f2, NV, PV, HAV, ADV type 40, and FCV, 25,26,44,45 and so we concluded that the reaction rates of ClO 2 with EV71 were pH-dependent. Noss and Olivieri hpothesized that the results may have been attributable to a change in the chemical structure of the virion and/or the concentration of hydroxyl ions in the solution, if the hydroxyl ions were necessary for the inactivation reaction to occur. ...
... Additionally, CD has been ap-proved for use as a sterilant/decontaminant by the United States Environmental Protection Agency (U.S. EPA, 2005). Both gaseous and aqueous phase CD have been shown to be effective sanitizing agents that have broad and high-biocidal effectiveness against bacteria (Benarde et al., 1965;Harakeh et al., 1985;Ridenour et al., 1949) including pathogens (Harakeh et al., 1985;Korich et al., 1990;Roberts & Raymond, 1994), viruses (Chen & Vaughn, 1990;Noss & Oliver, 1985), bacterial spores (Ridenour et al., 1949), algae (White, 1972), and various chemicals and compounds (Bakhmutova-Albert et al., 2008;Rodriguez et al., 2007;Ryan et al., 2007). ...
Article
Allergic reactions to beta-lactams, such as penicillin, can be life-threatening. Due to the large number of individuals allergic to beta-lactams, a method for their inactivation was explored such that a contaminated area could be treated and re-used. The goal was to validate a cycle that could be used to treat a pharmaceutical manufacturer's beta-lactam manufacturing equipment for the future production of non-beta-lactam compounds. Testing was conducted using chlorine dioxide gas at various concentrations and exposure times in an effort to achieve the pharmaceutical manufacturer's required 3-log (99.9%) reduction of eight different beta-lactams on various surfaces. After a period of cycle development, multiple chlorine dioxide gas cycles at various concentrations and exposure lengths were shown effective in inactivating the eight beta-lactam compounds to a successful degree.
... However, Zhang and Farber (1996) found no signi®cant difference in decontamination ef®ciency between chlorine and chlorine dioxide. Several authors have reported the sensitivity of a range of animal viruses to chlorine dioxide (Harakeh 1987;Chen and Vaughn 1990) although there is no information for NLVs and hepatitis A virus. ...
Article
Raw and minimally processed fruits and vegetables are typically sold to the consumer in a ready-to-use or ready-to-eat form. These products do not generally contain preservatives or antimicrobial agents and rarely undergo any heat processing prior to consumption. For many years raw fruits and vegetables have been implicated as vehicles for transmission of infectious micro-organisms. Although fresh produce can support the growth and/or survival of many pathogenic bacteria there is little published information on the stability of human pathogenic viruses on these food products. Viruses cannot grow in or on foods but may sometimes be present on fresh produce as a result of faecal contamination. This contamination can arise at source in the growth and harvesting area from contact with polluted water and inadequately or untreated sewage sludge used for irrigation and fertilization. Alternatively, fruits or vegetables handled by an infected person might become contaminated with virus and transmit infection. The most frequently reported foodborne viral infections are viral gastroenteritis and hepatitis A: both have been associated with the consumption of fresh fruit or vegetables.
... Studies have proved the efficacy of ClO 2 on a wide variety of microorganisms and viruses. Chen and Vaughn (1990) demonstrated activity of ClO 2 against rotaviruses and reviewed early works on its virucidal efficacy at alkaline conditions. ClO 2 can also decrease the viability of Cryptosporidium parvum oocysts (Peeters, Ares, Masschelein, Villacorta, & Debacker, 1989), but not until safe levels (Korich, Mead, Madore, Sinclair, & Sterling, 1990). ...
Article
Minimally processed fruits and vegetables (MPFV) have a short shelf-life due to their metabolism and the action of spoilage microorganisms. Chlorine dioxide is a powerful oxidizing agent that can be used as decontaminant. It does not form significant amounts of chlorinated by-products like as do chlorine. This article revises the characteristics of chlorine dioxide, the basis of its antimicrobial action, and its effect on microorganisms and on the sensory quality and shelf-life of fresh produce and mainly MPFV. Moreover, it discusses its effects on the physiology and nutritional quality of MPFV, and provides information on its toxicity and legal status.
... As in most healthcare facilities around the world, disinfection of the SHCs in Taiwan is accomplished using chlorine dioxide (ClO 2 ). ClO 2 can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans (Taylor and Butler 1982;Chen and Vaughn 1990;Sivaganesan et al. 2003;Loret et al. 2005;Lu et al. 2004). ClO 2 dissolves readily in water, forming a stable state of small particles. ...
Article
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In Taiwan, the immediate health care requirements of students and faculty members are satisfied by on-campus medical service centers. The air quality within these centers should comply with the guidelines laid down by the Taiwan Environmental Protection Agency (EPA). Accordingly, this study performed an experimental investigation into the efficiency of various chlorine dioxide applications in disinfecting a local student health center (SHC). The air quality before and after disinfection were evaluated in terms of the bioaerosol levels of bacteria and fungi. The average background levels of bacteria and fungi before disinfection were found to be 1,142 ± 455.4 CFU/m(3) and 520 ± 442.4 CFU/m(3), respectively. Chlorine dioxide (0.3 mg/m(3)) was applied using three different methods, namely a single, one-off application, multiple applications within a single day, and regular (daily) applications. Among the three disinfection methods, the regular application method was found to yield a high disinfection efficiency for both bacteria and fungi, i.e., 6.5 ± 0.7% and 4.2 ± 0.3%, respectively. The average residual bacteria and fungi levels after regular daily interval disinfection were 318.8 ± 51.5 CFU/m(3) and 254.0 ± 43.8 CFU/m(3), respectively. Therefore, the results suggest that the air quality guidelines prescribed by the Taiwan EPA for SHCs and other healthcare facilities can best be achieved by applying chlorine dioxide at regular (daily) intervals.
... ClO 2 effectively inactivates micro-organisms in water and inactivation of several water related pathogenic viruses has been reported (Alvarez and O'Brien, 1982;Chen and Vaughn, 1990;Thurston-Enriquez et al., 2005;Berman and Hoff, 1984;Lim et al., 2010b). Most of these studies used relative high concentrations of ClO 2 in combination with short contact times, but in water applications frequently low concentrations are dosed, and inactivation is achieved by long contact time. ...
Article
This study investigates the effects of very low concentrations of ClO(2) applied in drinking water practice on the inactivation of bacteriophage MS2. Concentrations of 0.5 mg/L, 0.1 mg/L and 0.02 mg/L ClO(2) inactivated at least 5 log units of MS2 after an exposure time of approximately 20, 50 and 300 min respectively. When the ClO(2) concentration was as low as 0.005 mg/L, inactivation of 1 log unit MS2 was observed after 300 min exposure. Increasing the contact time to 24 h did not increase the inactivation any further. Non-linear inactivation kinetics (tailing) were observed for all conditions tested. Repeated addition of MS2 to the reactor showed that tailing was not caused by a reduction of the biocidal effect of ClO(2) during disinfection. The Modified Chick-Watson, the Efficiency Factor Hom (EFH) model and the Modified Cerf model, a modification of the two-fraction Cerf model, were fitted to the non-linear inactivation curves. Both the EFH and the modified Cerf model did fit accurately to the inactivation data of all experiments. The good fit of the Modified Cerf model supports the hypothesis of the presence of two subpopulations. Our study showed that ClO(2) is an effective disinfectant against model organism MS2, also at the low concentrations applied in water treatment practice. The inactivation kinetics followed a biphasic pattern due to the presence of a more ClO(2)-resistant subpopulation of MS2 phages, either caused by population heterogeneity or aggregation/adhesion of MS2.
... In summary, and as reported previously, aqueous ClO 2 possesses bactericidal, viricidal, and sporicidal properties at a dosage of 0.2-0.5 mg/L (Chen and Vaughn 1990;Medema et al. 1991;Whitmore and Denny 1992). Because of this, ClO 2 is regarded as a true chemosterilizing agent (Rosenblatt et al. 1985). ...
Article
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We found that the marine yeast Debaryomyces hansenii strain C-11 (CIBNOR yeast collection, La Paz, Mexico) is highly tolerant to chlorine dioxide (ClO2), a powerful biocide agent. A direct application of this observation is the fermentation of the yeast in a nonsterile medium with an initial concentration of 0.3 mg/L of ClO2. The disinfectant helps to avoid the growth of unwanted microorganisms while allowing the development of the yeast. Because the concentration of ClO2 decreases during the fermentation, we ascribe to D. hansenii cells a "biocontrol" action that contributes to the collection of a contaminant-free yeast cell biomass.
... However, Zhang and Farber (1996) found no signi®cant difference in decontamination ef®ciency between chlorine and chlorine dioxide. Several authors have reported the sensitivity of a range of animal viruses to chlorine dioxide (Harakeh 1987;Chen and Vaughn 1990) although there is no information for NLVs and hepatitis A virus. ...
... In another study, rotavirus was sensitive to o-phenylphenol and ethanol and chlorine bleach (Sattar et al., 1994). Rotavirus was readily inactivated by chlorine dioxide at alkaline pH (Chen and Vaughn, 1990), and by chlorine (Vaughn et al., 1986) and ozone (Vaughn et al., 1987), especially at neutral to acidic pH. A number of enteroviruses were inactivated by chlorine, chlorine dioxide, peracetic acid, and ozone (Harakeh and Butler, 1984). ...
... For purposes of drinking water disinfection, much work has been done with respect to dissolved disinfectants as for example chlorine, ozone or chlorine dioxide. The kinetics for these treatments have been studied in depth for many different microorganisms 105,174,175 and the molecular-level mechanisms of inactivation are increasingly being investigated. 56,112 However, less is known about heterogeneous disinfection, i.e, inactivation processes involving surfaces or particles. ...
... Furthermore, the inactivation curve of E11 by ClO 2 exhibits a pronounced tail (Figure 2A). This feature has previously been reported for virus inactivation by ClO 2, and has been attributed to multiple causes, including the presence of resistant subpopulations or the gradual accumulation of protein oxidation products that form a protective layer on the viral capsid (Berman and Hoff, 1984;Chen and Vaughn, 1990;Thurston-Enriquez et al., 2005;Lim et al., 2010;Jin et al., 2013;Sigstam et al., 2013). The tailing inactivation curve may cause the extent of genome damage by ClO 2 to not scale linearly with inactivation, but instead to increasingly exceed the extent of inactivation ( Figure 5). ...
Article
Full-text available
The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2)- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat), and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.
... A potentially more effective disinfection method for some organisms is the application of ozone. Chen and Vaughn (1990) found that ozone was more effective at removing rotaviruses than chlorine, monochloramine and chlorine dioxide. It has also been found to be more efficient than free chlorine for the removal of viruses, bacterial spores and cysts by Mara and Horan (2013). ...
Book
Drinking water quality is of key importance to public health, and the provision of safe drinking water has been recognised as one of the greatest technological and public health advances of the last century. The current system of delivering safe water to consumers in the UK is based upon significant investment in infrastructure and performs at an excellent standard at a very low cost. However, the future challenges of climate change, energy efficiency, population growth, and an aging infrastructure mean that the traditional ways of providing safe water may need to change. If we want to achieve 100% compliance with drinking water standards (at point of use) by 2050 we need considerable research and development in this area. We have created a strategic research programme help us achieve this.
... In summary, and as reported previously, aqueous ClO 2 possesses bactericidal, viricidal, and sporicidal properties at a dosage of 0.2-0.5 mg/L (Chen and Vaughn 1990;Medema et al. 1991;Whitmore and Denny 1992). Because of this, ClO 2 is regarded as a true chemosterilizing agent (Rosenblatt et al. 1985). ...
... Therefore, this compound is commonly used as a strong disinfectant. Few studies have shown that some viruses can be successfully deactivated using ClO 2 , such as human rotavirus (Chen and Vaughn, 1990), HuNoV (Lim et al., 2010;Montazeri et al., 2017), FCV (Montazeri et al., 2017), enterovirus71 (Jin et al., 2013), poliovirus 1 (Simonet and Gantzer, 2006), and echovirus 11 (Zhong et al., 2017). Kingsley et al. (2014) reported a 2.8 log 10 reduction in HuNoV after 1 h of treatment with 350 ppm ClO 2 . ...
Article
Full-text available
A carrier (stainless steel disc as a default carrier) testing method is very needed for use in the actual food-processing fields by following the standard guideline. Here, we aimed to compare the virucidal efficacy of four commercial liquid disinfectants, including sodium hypochlorite (NaOCl), chlorine dioxide (ClO2), and peracetic acid (PAA) against hepatitis A virus (HAV) following the OECD guideline protocol based on the quantitative carrier testing method and compared carrier testing results with the suspension testing results. The OECD method specifies a test for establishing whether a chemical disinfectant or a microbicide has a virucidal activity on hard non-porous surfaces. The antiviral efficacy was evaluated by plaque assays, and disinfectants were considered effective if the virus reduction was greater than or equal to 3 log10 (99.9% decrease) for carrier or 4 log10 (99.99% decrease) for suspension tests. Results indicated that ClO2 above 500 ppm and 50% ethanol were effective in the carrier test method. In contrast, more than 200 ppm NaOCl and 50 ppm ClO2 for all exposure times and 70% ethanol with contact for more than 5 min were effective in suspension tests. Treatment with PAA (80–2500 ppm) were not effective in carrier or suspension tests. Therefore, we recommend the use of more than 500 ppm ClO2 or 50% ethanol with exposure for 10 min to disinfect surfaces that may be contaminated with HAV. Thus, these results could be effective in establishing official antiviral efficacy testing methods and basic data.
... Cromeans et al. systematically compared the performance of chlorine on the inactivation of EV2, EV40, EV41, CVB3, CVB5, ekovirus 1, ekovirus 11 and murine NoV, and found CVB5 to show the strongest resistance to chlorine, whereas murine NoV exhibited the least resistance [162]. Similarly, the resistance of typical viruses to chlorine dioxide declined as follows: HRoV > coxsackie virus > echovirus > PV > f2 phages > monkey RoV [15,[163][164][165]. Compared to chlorine dioxide, chlorine exhibited a much higher inactivation efficiency for SARS-CoV and SARS-CoV-2, which could be proven by the observation of complete inactivation of SARS-CoV by 20 mg⋅L − 1 chlorine after a 1 min reaction [58,166]. ...
Article
The ongoing coronavirus pandemic (COVID-19) throughout the world has severely threatened the global economy and public health. Due to receiving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a wide variety of sources (e.g., households, hospitals, slaughterhouses), urban sewage treatment systems are regarded as an important path for the transmission of waterborne viruses. This review presents a quantitative profile of the concentration distribution of typical viruses within wastewater collection systems and evaluates the influence of different characteristics of sewer systems on virus species and concentration. Then, the efficiencies and mechanisms of virus removal in the units of wastewater treatment plants (WWTPs) are summarized and compared, among which the inactivation efficiencies of typical viruses by typical disinfection approaches under varied operational conditions are elucidated. Subsequently, the occurrence and removal of viruses in treated effluent reuse and desalination, as well as that in sewage sludge treatment, are discussed. Potential dissemination of viruses is emphasized by occurrence via aerosolization from toilets, the collection system and WWTP aeration, which might have a vital role in the transmission and spread of viruses. Finally, the frequency and concentration of viruses in reclaimed water, the probability of infection are also reviewed for discussing the potential health risks.
... There is evidence of virucidal activity of ClO2 against echovirus [15], enterovirus [16], poliovirus [17], rotavirus [18], norovirus [19,20], calicivirus [19], and coronavirus [21]. However, there are few publications that explore antiviral effects in vitro and in vivo. ...
Preprint
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Background The need for safe and effective antiviral treatments is pressing given the number of viral infections that are prevalent in animal and human populations, often causing devastating economic losses and mortality. Informal accounts of anecdotal use of chlorine dioxide (ClO 2 ), a well-known disinfectant and antiseptic, in COVID-19 patients has raised concern about potential toxicity, but also raises the question that ClO 2 might elicit antiviral effects, a possibility that has never been examined in vivo in any animal model. Here, we challenged the hypothesis that ClO 2 decreases the viral load and virus-induced mortality in a vertebrate model. For this, we determined viral load, virus-induced lesions and mortality in 10-day old chick embryos inoculated with 10 ⁴ mean EID 50 /mL of attenuated Massachusetts and Connecticut avian coronavirus (IBV) strains. Results The ClO 2 treatment had a marked impact on IBV infection. Namely, viral titres were 2.4-fold lower and mortality was reduced by half in infected embryos that were treated with ClO 2 . Infection led to developmental abnormalities regardless of treatment. Lesions typical of IBV infections were observed in all inoculated embryos, but severity tended to be significantly lower in ClO 2 -treated embryos. We found no gross or microscopic evidence of toxicity caused by ClO 2 at the doses used herein. Conclusions Our study shows that ClO 2 could be a safe and viable way of treating and mitigating the effects of avian coronavirus infections, and raises the possibility that similar effects could be observed in other organisms. Graphical abstract
... Studies have proved the efficacy of ClO 2 on a wide variety of microorganisms and viruses. Chen and Vaughn (1990) demonstrated activity of ClO 2 against rotaviruses and reviewed early works on its virucidal efficacy at alkaline conditions. ClO 2 can also decrease the viability of Cryptosporidium parvum oocysts (Peeters, Ares, Masschelein, Villacorta, & Debacker, 1989), but not until safe levels (Korich, Mead, Madore, Sinclair, & Sterling, 1990). ...
Chapter
Chlorine dioxide (CAS 10049-04-4) is a strong oxidizing agent, bactericide, fungicide, algicide, and antiseptic. It is used as a bleaching agent in the pulp mill industry and as a disinfectant for public water supplies. It is an intended substitute of chlorine for many applications because it generates fewer chlorination byproducts. Chlorine dioxide can be used in gaseous and liquid forms, which have different toxicological importance. The gas has relevance as an irritant of eyes, skin, and respiratory tracts of exposed workers. Consumption of water disinfected with chlorine dioxide is the most common exposure route for the general population. It is not environmentally persistent; it degrades in water quickly to chlorite, which is toxic and more stable. There is no evidence of immunotoxicity, reproductive toxicity, or carcinogenicity of chlorine dioxide and evidence in favor of genotoxicity is conflicting.
... The generation of gaseous chlorine dioxide (ClO 2 ) is one of several techniques available for the remediation of structures impacted by microbial growth (US EPA 2007). ClO 2 can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans (Taylor and Butler 1982;Chen and Vaughn 1990;Sivaganesan et al. 2003;Loret et al. 2005). Furthermore, ClO 2 dissolves readily in water, forming a stable state of small particles. ...
Article
Full-text available
Many studies have shown that pet shops have a high concentration of bioaerosols. Thus, effective disinfection protocols are essential to protect the pet shop staff and visitors to the store. The present study examines the effectiveness of gaseous chlorine dioxide (ClO2) fogging in minimizing the residual bacteria and fungi levels in a typical pet shop in Taiwan consisting of a commodity area, a lodging area, and a grooming area. This investigation uses three disinfection modes (DMs) according to different disinfection periods, namely once every hour (1DM), once every 2 h (2DM), and once every 3 h (3DM). The bacteria and fungi concentrations are measured before and after disinfection treatment, and the effectiveness of each disinfection mode is evaluated using standard statistical techniques. To assess the effect of the environmental factors on the disinfection efficiency, measurements are taken of temperature, relative humidity, airflow velocity, the carbon dioxide concentration, the PM1, PM2.5, PM7, PM10, and TSP level at each sampling locations. The results reveal that the effectiveness of the three disinfection modes depends on both the environmental parameters and the use of the three areas (e.g., commodity, lodging, or grooming). Hence, the choice of disinfection method should be adjusted accordingly. For all three disinfection modes, a faster air velocity is beneficial in spreading the disinfectant throughout the indoor space and improving the disinfection performance. Overall, the results presented in this study confirm that gaseous chlorine dioxide disinfection improves the air quality in the pet shop interior, and thus beneficial in safeguarding the health of the pet shop staff and visitors.
... Chlorine dioxide is an excellent bactericidal agent, as has been reported in various studies, although its virucidal activity has not been thoroughly investigated as yet [6][7][8][9][10][11][12]. The inactivation kinetics of Poliovirus 1 under experimental conditions have shown that it has a good oxidizing effect [13]. ...
Presentation
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La legalización en Bolivia del uso oral del Dioxido de Cloro y sus excelentes resultdos, nos lleva a hacer este trabajo Estamos acostumbrados, en los estudios Biologicos, a enfoques mas Bioquímicos que Biofisicos. La explicación seria la mayor proximidad entre la Química y la Biología. Pero es necesario advertir que existe una dinámica Física que origina, en el fondo, esa diversidad Bioquimica y desde unos fundamentos mas basicos se puede esclarecer y simplificar esa diversidad bioquimica Solo haría falta observar los trabajos: Proposed informational code of biomolecules and its building blocks: quantum coherence versus decoherence https://www.researchgate.net/publication/340675518_Proposed_informational_code_of_biomolecules_and_its_building_blocks_quantum_coherence_versus_decoherence https://www.researchgate.net/publication/333844547_Statistical_analysis_and_prospective_application_of_the_GM-scale_a_semi-harmonic_EMF_scale_proposed_to_discriminate_between_%27coherent%27_and_%27decoherent%27_EM_frequencies_on_life_conditionshttps://www.researchgate.net/requests/r81749014 Sobre el por qué y el cómo de la importancia de los minerales arcillosos en el surgimiento de la vida https://www.researchgate.net/publication/342401364_On_the_why%27s_and_how%27s_of_clay_minerals%27_importance_in_life%27s_emergence Para darse cuenta de que un simple mineral, pueden inducir estructuras bioquímicas. Debemos investigar esa Dinámica Universal, que fundamentada en principios básicos como el número de oro, secuencia de fibonacci, fractales, escala musical…etc.…sustentan y generan toda la diversidad bioquímica.
... ClO 2 is regarded as a potent and suitable disinfectant widely used in recent years. Many studies have certified that several viruses were inactivated effectively by the chlorination of ClO 2 , including human rotavirus (HRV) (Chen and Vaughn, 1990), human norovirus (HNoV) (Lim et al., 2010;Montazeri et al., 2017), feline calicivirus (FCV) (Montazeri et al., 2017), enterovirus71 (EV71) (Jin et al., 2013), poliovirus 1 (PV1) (Simonet and Gantzer, 2006) and echovirus 11 (E11) (Zhong et al., 2017). However, the mechanism that the inactivation of PRRSV by ClO 2 has not been reported. ...
Article
Porcine reproductive and respiratory syndrome virus (PRRSV) causes a great economic loss to the swine industry globally. Current prevention and treatment measures are not effective to control the outbreak and spread of porcine reproductive and respiratory syndrome (PRRS). In other words, new antiviral strategies are urgently needed. Chlorine dioxide (ClO2) is regarded as a broad-spectrum disinfectant with strong inhibitory effects on microbes and parasites. The purpose of this study was to evaluate the inhibitory effects and underlying molecular mechanisms of ClO2 against PRRSV infection in vitro. Here, we identified ClO2 (the purity is 99%) could inhibit the infection and replication of PRRSV in both Marc-145 cells and porcine alveolar macrophages (PAMs). ClO2 could block PRRSV binding to cells rather than internalization and release, suggesting that ClO2 blocks the first stage of the virus life cycle. We also demonstrated that the inhibition exerted by ClO2 was attributed to the degradation of PRRSV genome and proteins. Moreover, we confirmed that ClO2 could decrease the expression of inflammatory cytokines induced by PRRSV. In summary, ClO2 is an efficient agent and potently suppressed PRRSV infection in vitro.
Article
Emergence and re-emergence of four types of severely infectious viruses have claimed significant numbers of lives when anthropogenic activities contribute to the mutagenesis of these pathogens and infectivity of these pathogens has been noticeably altered. However, both point and non-point sources can transport these viruses in water treatment and resource recovery facilities (RRF) where the presence of these pathogens in aerosolized form or in suspension can cause astronomical public health concerns. Hence, numerous scientific studies have been reviewed to comprehend the possible inactivation mechanisms of those viruses in aqueous phase where thermal-, photo-, and chemical-inactivation have confirmed their effectiveness in restraining those viruses and inactivation mechanisms are the major focuses to apprehend the quick and cost-effective virus removal process from water and RRF. Although practical applications of nano-sized disinfectants have challenged researchers, those disinfectants can completely kill the viruses and hamper RNA/DNA replication without any sign of reactivation or repair. Moreover, limitations and future research potential are discussed so that efficacious strategic management for a treatment facility can be developed at the forefront of fighting tactics against an epidemic or a pandemic. Enumerations, besides state-of-the-art detection techniques with gene sequences, are mentioned for these viruses. HIGHLIGHTS UV and FUVC can effectively inactivate corona- and ebolaviruses.; Nanostructured disinfectants have potential to inactivate the emerging viruses by forming ROSs in both solid and liquid phase.; Disintegration of capsid protein and nucleic acid is imperative to inactivate viruses.; A strategic framework to develop early warning in the community should be established.; This kind of review manuscript is extremely rare.;
Article
Onsite wastewater management systems with irrigation are affordable and they are also easy to operate. Distribution of wastewater in public places such as lawns, parks, and golf courses is a common feature in wastewater reuse systems. However, it poses a health hazard to the public and people that are exposed to the irrigated wastewater when it is not adequately disinfected. This results in spread of infectious waterborne diseases such as gastroenteritis, cryptosporidiosis, and giardiasis. A new alternative to wastewater disinfection in the form of a small packet has been developed by Avantec Technologies. Chlorine dioxide gas is produced when the packet containing reactants is exposed to moisture or immersed in water. Among several advantages of using chlorine dioxide for wastewater disinfection, the most significant is its ability to kill viruses and parasites. Product design fundamentals such as problem decomposition methods and function diagrams were used to identify the functions of the delivery device design The delivery device comprises a top rack, a bottom rack, a wastewater drum, a circulating pump, and a wastewater storage tank. When a chlorine dioxide packet from the top rack is dropped into the bottom rack of the chlorine dioxide device, wastewater from the tank will be circulated into the wastewater drum enclosing the bottom rack. Chlorine dioxide gas is generated as a result and it mixes with the circulating wastewater to form a chlorine dioxide solution. The dropping of a chlorine dioxide packet is timed and controlled according to wastewater level in the tank.
Article
A multicomponent evaluation of the oxidative consumption of salivary biomolecules by a commercially-available oral rinse preparation containing an admixture of the stable free radical species chlorine dioxide (ClO2.) with chlorite anion (ClO2-) has been investigated using high resolution H-1 NMR spectroscopy. The results obtained demonstrated that ClO2. and/or ClO2- present in this preparation effected the oxidative decarboxylation of salivary pyruvate (to acetate and CO2). Experiments conducted on chemical model systems confirmed the oxidative decarboxylation of pyruvate by this oral rinse, and also demonstrated that urate, thiocyanate anion, and the amino acids cysteine and methionine (precursors to volatile sulphur compounds responsible for oral malodour), were oxidatively consumed. The biochemical, periodontal and therapeutic significance of the results are discussed.
Article
Da recenti studi epidemiologici è emerso che i virus enterici, in particolare i norovirus (NV), il virus a dell’epatite (HAV) e rotavirus (RV), sono un importante causa di gastroenteriti nei paesi in via di sviluppo. La contaminazione degli alimenti può avvenire in diversi momenti della filiera alimentare, ad esempio possono essere le materie prime ad essere contaminate, oppure la contaminazione può avvenire durante le fasi della lavorazione. Questo può verificarsi perché durante la produzione gli alimenti possono essere manipolati da personale infetto o entrare in contatto con acqua contaminata. Ad eccezione dei molluschi bivalvi sugli alimenti non vengono effettuate analisi virologiche. Diverse epidemie gastroenteriche sono di sospetta origine virale, ma questo non è sempre dimostrabile a causa di carenza di tecniche sensibili ed efficaci per il rilevamento virale. La sicurezza di un alimento quindi difficilmente può essere determinata da analisi virologiche e risulta perciò molto importante intervenire a livello di prevenzione della contaminazione implementando le misure di sanificazione degli impianti e di igiene del personale in modo da inattivare ed eliminare i possibili microrganismi patogeni di contaminazione. In questo lavoro sono state condotte prove di inattivazione virale con alcuni degli agenti ossidanti impiegati nella disinfezione degli impianti al fine di ricavare idonee combinazioni tempo di contatto-concentrazione per l’inattivazione virale. In oltre si è proceduto alla messa appunto di una metodica di rilevamento virale da campioni alimentari. Recent epidemiological evidence indicates that enteric viruses, in particular norovirus (NV), which cause acute gastroenteritis, but also hepatitis A virus (HAV) and rotavirus (RV), are the leading cause of foodborne illness in developed countries Foods may be contaminated during cultivation before harvest by contact with inadequately treated sewage or sewage polluted water. Contamination may also occur during processing, storage, distribution or final preparation. This could happen because food is contacted by infected people, contaminated water, or fomites. However, except for shellfish, foods are seldom tested for viruses. Frequently, foodborne outbreaks are suspected of being caused by viruses but, because of the lack of sensitive and reliable methods, this suspicion can rarely be confirmed by isolation of the virus from the implicated food. Hence the safety of food products cannot be assured by testing for viruses, but can be by the prevention of contamination and the implementation of manufacturing processes disinfection that inactivate or eliminate them. The aim of this work was to assess the efficacy of some chemical disinfectant on certain enteric viruses through the kinetics of inactivation performed under experimental conditions. It will be possible to use the results thus obtained to set up time-concentration models to be applied to food processing plants. Moreover this work concerns the definition and assessment of a method to extract viruses from foodstuffs.
Article
An infection control problem in dental operatories which is not fully controlled is waterline contamination by heterotrophic mesophilic bacteria. These bacteria are present in water supplies as a planktonic phase and adhere to the lumen of tubings as a biofilm comprised of their external cell surface glycocalyx and by production of extracellular carbohydrate polymers. The adherent film is most difficult to remove. The accumulated planktonic phase can be reduced significantly by flushing water from the lines before use in patient treatment, but will return when the equipment is idle through the accumulation of more planktonic phase and by slough of the biofilm surface-adsorbed phase not yet enmeshed in the carbohydrate matrix. Chlorine dioxide has antimicrobial activity against many bacteria, spores, and viruses. It is used in water supply treatment as a disinfectant and slime preventive and has an advantage over chlorine in that carcinogenic trihalomethanes are not generated. This study compared use of phosphate buffer-stabilized chlorine dioxide (0.1%) mouthrinse as a lavage in ultrasonic dental scaler units with the use of tap water as a control. Sterile water flushed through the units onto heterotrophic plate count (HPC) sampler plates was cultured 7 days at room temperature and colonies were counted at 12x. One test and one control unit were used for biopsy of internal tubing and scanning electron microscopy imaging. The HPC counts, in colony forming units (CFU)/ml, were reduced 3- to 5-fold by flushing tap water through the units, but they returned after units were idle overnight. When phosphate-buffered chlorine dioxide mouthrinse was used as a lavage, CFU/ml were reduced 12- to 20-fold. Holding chlorine dioxide in waterlines overnight reduced recurrent buildup compared to water (P <0.05). Scanning electron microscopy images indicated a significant reduction of biofilm coverage by chlorine dioxide as compared to water (P<0.001). Phosphate-buffered chlorine dioxide mouthrinse was effective in these short-term trials for control of waterline contamination in ultrasonic dental scaling units. It should prove as useful in dental professional waterline applications as it has in industrial uses for biofilm control.
Article
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Hepatitis A and E viruses, rotaviruses, Norwalk-like caliciviruses, and astroviruses are among the enteric viruses known to cause food- and waterborne illness. These viruses are spread by the fecal-oral route and are a major cause of morbidity and mortality worldwide. Foods may be contaminated at any time pre- or post-harvest; however, many outbreaks are associated with foods handled by infected restaurant workers. Produce may be contaminated by improper irrigation or fertilization practices, by the hands of infected pickers or processors, or as the result of adulteration during any stage of handling. Outbreaks have been commonly associated with foods which are served raw or only lightly cooked, such as molluscan shellfish, fruits and vegetables, and salads or products contaminated after cooking like frosted bakery products. The farming, shellfish, processing, transportation, and restaurant industries must maintain vigilance to reduce outbreaks of enteric virus illness. Intervention strategies to enhance product safety include increased industry and consumer education; changes in industrial practices, product management, and processing technologies; worker immunizations; and the development of improved monitoring tools for the detection of enteric viruses in foods.
Chapter
Humic substances (HS) improve soil fertility and structure, control nutrient uptake, and root architecture to increase plant growth and productivity. These modifications’ underlying biochemical and molecular mechanisms remain little understood. Colloidal dispersal systems have been discovered in HS, and although there is scant evidence to support this theory, it has been hypothesized that complex organic chemicals are already at work. In the book’s chapters, the authors give a summary of the findings that is currently available regarding the composition, biosynthesis, humification, and biological functions of humic compounds, with an emphasis on their surfaceactive characteristics. The biggest source of recalcitrant organic carbon in the terrestrial ecosystem, HS are an analytically defined percentage of soil organic matter. Where this book chapter explains the importance of humic substances as an essential environmental component for human life. They are very complex materials that need an explanation and simplification of how they are influencing the human life, so the reader will find in this book chapter a detailed explanation of how they are formed and structured in the soil. The authors explain the correction factors misconceptions about humic substances.
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Many resources and much effort has been devoted to viral inactivation studies due to potential serious health implications associated with viral contamination. Sulfur dioxide has been evaluated to determine its potential to inactivate reovirus and poliovirus. Reovirus (PIV or IV) in wastewater was inactivated with SO2 treatment by 90%. Poliovirus in wastewater was ionactivated by 97% with a 500 mg/L SO2 treatment.
Article
  Over one-half of foodborne illnesses are believed to be viral in origin. The ability of viruses to persist in the environment and foods, coupled with low infectious doses, allows even a small amount of contamination to cause serious problems. An increased incidence of foodborne illnesses and consumer demand for fresh, convenient, and safe foods have prompted research into alternative food-processing technologies. This review focuses on viral inactivation by both traditional processing technologies such as use of antimicrobial agents and the application of heat, and also novel processing technologies including high-pressure processing, ultraviolet- and gamma-irradiation, and pulsed electric fields. These industrially applicable control measures will be discussed in relation to the 2 most common causes of foodborne viral illnesses, hepatitis A virus and human noroviruses. Other enteric viruses, including adenoviruses, rotaviruses, aichi virus, and laboratory and industrial viral surrogates such as feline caliciviruses, murine noroviruses, bacteriophage MS2 and ΦX174, and virus-like particles are also discussed. The basis of each technology, inactivation efficacy, proposed mechanisms of viral inactivation, factors affecting viral inactivation, and applicability to the food industry with a focus on ready-to-eat foods, produce, and shellfish, are all featured in this review.
Article
The inactivation effect of chlorine, iodine, ozone and UV irradiation was compared between phosphate buffered saline and waste water collected from a fish farm, with the fish-pathogenic bacterium Aeromonas salmonicida subsp. salmonicida as the model organism. In addition, the effect of combining chlorine, iodine or ozone with UV was evaluated. A tenfold increase in initial chlorine concentration, from 0.2 to 2.0 mg l−1. had to be applied to maintain the same level of inactivation in waste water as in PBS. Iodine was less efficient than chlorine in PBS. by demanding a concentration of 1.0 mg l−1 to obtain the same rate of inactivation as with 0.2 mg l−1 chlorine. However, no difference between the two halogens was evident in the low-quality water. An initial ozone concentration of 0.1 mg l−1 in PBS caused a rapid drop in bacterial viability for the first 20 s after which the curve levelled off. By continuous ozonation of waste water, a residual oxidant concentration of about 0.3 mg l−1 had to be established before a rapid inactivation was observed. The UV inactivation profiles in PBS and waste water were almost identical, with a 99.9% reduction in viability after 48 and 50 s. respectively. When UV irradiation was combined with chlorine, a less than additive effect, as compared with the sum of individual death rates by the two treatments, was observed. The corresponding UV/iodine combination at least gave an additive effect in both water qualities. No increment in inactivation rate in PBS was observed when ozone was used in combination with UV, as compared with ozone alone.
Article
Despite the health risks posed by waterborne human rotavirus (HRV), little information is available concerning the effectiveness of chlorine or chlorine dioxide (ClO2), two common disinfectants of public water sources, against HRV and their effects on its genome remain poorly understood. This study investigated the effects of chlorine and ClO2 on purified HRV by using cell culture and RT-PCR to assess virus infectivity and genetic integrity, respectively. The disinfection efficacy of ClO2 was found to be higher than that of chlorine. According to the efficiency factor Hom model, Ct value (mg/L min) ranges required for a 4-log reduction of HRV at 20 °C by chlorine and ClO2 were 5.55-5.59 and 1.21-2.47 mg/L min, respectively. Detection of the 11 HRV genome segments revealed that damage to the 1227-2354 bp of the VP4 gene was associated with the disappearance of viral infectivity by chlorine. However, no complete accordance between culturing and RT-PCR assays was observed after treatment of HRV with ClO2. These results collectively indicate that the current practice of chlorine disinfection may be inadequate to manage the risk of waterborne HRV infection, and offer the potential to monitor the infectivity of HRV adapting PCR-based protocols in chlorine disinfection.
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This study investigates the mechanisms underlying the deviation from Chick-Watson kinetics, namely a tailing curve, during the disinfection of viruses by chlorine dioxide (ClO2). Tailing has been previously reported, but is typically attributed to the decay in disinfectant concentration. Herein, it is shown that tailing occurs even at constant ClO2 concentrations. Four working hypothesis to explain the cause of tailing were tested, specifically changes in the solution's disinfecting capacity, aggregation of viruses, resistant virus subpopulations, and changes in the virus properties during disinfection. In experiments using MS2 as a model virus, it was possible to rule out the solution's disinfecting capacity, virus aggregation and the resistant subpopulation as reasons for tailing. Instead, the cause for tailing is the deposition of an adduct onto the virus capsid over the course of the experiment, which protects the viruses. This adduct could easily be removed by washing, which restored the susceptibility of the viruses to ClO2. This finding highlights an important shortcoming of ClO2, namely its self-limiting effect on virus disinfection. It is important to take this effect into account in treatment applications to ensure that the water is sufficiently disinfected before human consumption.
Conference Paper
This research focused on the investigation on the removal efficiency of pathogenic bacteria and human viruses to produce safe wastewater reclamation and reuse for agricultural purposes. Under existing wastewater treatment processes, only 1-2 logs removal could be achieved of various targets of pathogens. Therefore, further treatment was required to comply with the water reuse guideline established by World Health Organization (WHO). Investigations were conducted using model microorganisms to evaluate the performance of advance treatment technology including ultraviolet (UV) and ozonation (O3). A few logs reduction could be achieved with minimum dose of UV and ozonation. This research concluded that UV and ozonation could achieve 2-5logs pathogen removal for wastewater reclamation and reuse suitable for agriculture activity.
Chapter
The microalgae are showing their future perspectives in the phytoremediation technology to clean water, recapture waste nutrients, degrade pollutants and convert them to economically valuable bio-based products. Algae can produce high biomass by using the wastewater and can be utilized to produce biofuels by using the existing technology. This algal green technology has been accepted worldwide due to its vast environmental benefits. Genetic engineering has an immense role in algal bioremediation, such as it enables them to enhance their growth, and helps to give resistance to harsh environments. This chapter is mainly focusing on the advancements of genetic engineering improvement for bioremediation along with the feasibility of low-cost technology for algal biomass utilization. It also aims to improve the scientific attention to the future research perspectives in the field of engineered microalgae in bioremediation for economic and environmental sustainability.
Chapter
This chapter surveys the major microbial pathogens and parasites which may contaminate drinking water. Pathogens can be transmitted from the reservoir to a susceptible host by various routes. The most common route of transmission of infectious agents is from person to person. When contaminated with human and animal wastes, water contributes to waterborne diseases, water-washed diseases, water-based diseases and water-related diseases. Some diseases can be spread by airborne transmission. Some pathogens may be transmitted by nonliving objects or fomites. The three categories of pathogens generally encountered in aquatic environments are bacterial pathogens, viral pathogens and protozoan parasites. The chapter briefly discusses the main bacterial infectious agents that may be encountered in drinking water. It also talks about the major waterborne pathogenic protozoa which may potentially affect humans through consumption of contaminated drinking water.
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Disinfection against four enveloped animal disease viruses and two non-enveloped viruses (foot-and-mouth disease virus (FMDV) and swine vesicular disease virus (SVDV)) using nano pico ozone water was studied. Aclear disinfecting effect of this ozone water was observed with more than 100ml in volume (4mg/l), but the effect was observed immediately after mixing. The effective concentration against enveloped viruses and FMDV was 1mg/l, but more than 3mg/l was required for SVDV. The disinfecting effect of ozone water was influenced by organism contamination, but the disinfecting effect was continued 60min after generation against enveloped viruses and FMDV. Nano pico ozone water could be used for disinfection against animal disease viruses, because of its effectiveness at low concentrations and immediate effect.
Article
Disinfection against foot-and-mouth disease virus (FMDV) and swine vesicular disease virus (SVDV) placed in two kinds of animal experimental rooms by pure ozonegas were examined. The disinfecting effect of ozone gas was influenced by the quantities of viral materials, but a clear disinfectant effect against two viruseswas observed over 4mg/l of ozone concentration. FMDV was completely eliminated by ozone gas but a small amount of SVDV remained after disinfection. From these results, ozone gas could be used for disinfection against FMDV. Ozone gas was considered for use for vapor disinfection instead of formalin vapor disinfection.
Thesis
Même si les traitements thermiques ou la désinfection par les oxydants ont démontré leur efficacité virucide, les mécanismes liés à la perte du caractère infectieux ne sont pas connus. Ceci pose un réel problème d’interprétation de la présence de génome viral en matière de risque infectieux dans les aliments. Ce travail de thèse a pour objectif d’étudier l’évolution des propriétés de surface (charge et hydrophobie) de virus modèles, bactériophage MS2 et norovirus murin, au cours de l’inactivation par la chaleur, l’hypochlorite de sodium et l’ozone. Pour nos deux virus, nous démontrons l’existence d’une température critique au-delà de laquelle la particule virale se déstructure en libérant son génome. Un simple traitement à la RNase permettrait alors de ne détecter que des virus infectieux par biologie moléculaire. Le traitement thermique implique aussi une augmentation de l’hydrophobie soulignant des modifications conformationnelles de la capside. L’hypochlorite de sodium ne modifie que peu les propriétés de surface mais des phénomènes d’oxydation ont lieu au niveau de la capside puisque la charge du bactériophage MS2 est légèrement modifiée. Ces modifications diminuent la résistance thermique du virus. Nous démontrons un effet synergique de l’hypochlorite de sodium et la chaleur sur le bactériophage MS2 (inactivation, RNase et hydrophobie). Quant à l’ozone gazeux, nous soulignons son intérêt pour le traitement virucide des aliments fragiles. Ainsi, ce travail précise les mécanismes d’inactivation des virus et ouvre de nouvelles perspectives tant pour discriminer les virus infectieux et non-infectieux que pour proposer l’exploration de nouveaux traitements technologiques
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En la clínica veterinaria, los problemas de piel son la principal causa de la visita del paciente, en virtud que este órgano es un indicador de muchas afecciones locales o sistémicas. Dentro de las patologías presentes en la piel, se debe destacar a la dermatitis como la más común y es el resultado de muchos factores: infecciosos, metabólicos, anaeróbicos, alérgicos, atópicos, congénitos o incluso propios del medio ambiente o hábitat del animal. Las patologías más frecuentes son las infecciosas, entre ellas las micóticas, que se caracterizan por avanzar rápidamente, llegando a amenazar la vida del animal cuando no son tratadas de manera eficaz y a tiempo, de allí que se propusiera como objetivo de esta investigación, la de evaluar el uso de dióxido de cloro (ClO2) en gas, como tratamiento de dermatitis fúngicas en perros. Se seleccionaron 10 pacientes que asistieron a la consulta y que presentaban lesiones en piel, en la parte distal de las extremidades, que permitiera luego su introducción en una funda plástica, en donde entraría en contacto con el gas. Adicionalmente al tratamiento con el gas, se realizaron análisis hematológicos y bioquímicos pre y post-ensayo, para evaluar el estado de salud de los pacientes. Los resultados muestran que, solo en 3 de los 10 caninos sometidos al tratamiento con la forma gaseosa del dióxido de cloro (CDS) se mostraron signos de recesión de la micosis. Una recuperación que se aprecia de gran interes, más aún cuando se confirmó la ausencia del germen micótico que lo afectaba. A pesar de que solo un 30 % de los pacientes respondieron al tratamiento, CDS es un método potencial de terapia alternativa, sobre todo, en casos donde la resistencia medicamentosa se hace presente.
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A preparation of infectious human rotavirus, isolated from faeces and resuspended in wastewater effluent, was shown to be inactivated by chlorine, chlorine dioxide, ozone and peracetic acid. Infectivity was assayed in MA 104 cells by the detection of cell-associated viral antigen by immunofluorescence. The inactivation curves were similar to those reported for other enteric viruses. Human rotavirus was at least as resistant as poliovirus, coxsackievirus, echovirus and f2 coliphage and was strikingly less sensitive to inactivation than the simian rotavirus, SA11. The latter was generally the most sensitive of the six tested viruses yet is often taken as being representative of the human rotaviruses.
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Full-text available
Linhares A. C. (Institute Evandro Chagas, Fundaçäo Serviços de Saüde Publica, Ministério da Saüde, Belém, Pará, Brasil), F. P. Pinhelro, R. B. Freitas, Y. B. Gabbay, J. A. Shirley and G. M. Beards. An outbreak of rotavirus diarrhea among a nonimmune, isolated South American Indian community. Am J Epidemiol 1981; 113: 703-10. During July-August 1977, an outbreak of acute diarrhea occurred in an unusually isolated population, the Tiriyo indians, who live in the north of Para, Brazil, near the border with Surinam. Diarrhea was reported by 157 (70%) of the 224 Indians living in the village during the epidemic. There was one fatal case in a one year old child. Rotavirus was detected by electron microscopy in one fecal specimen collected from an acute case of diarrhea. Seroconver-sions were noted in 127 out of 168 (75.6%) paired serum samples tested for rotavirus antibody by counter-immunoelectrophoresls. With immunofluores-cence based neutralization tests, rotavirus serotype 1 (Birmingham) was shown to be associated with the outbreak. The Infection also boosted type 3 antibodies but this was most apparent in persons with pre-existing type 3 titers and the boost was not as great as with type 1. All age groups were affected. The proportion symptomatic was greatest in young children.
Article
We found chlorine dioxide to be a more effective disinfectant than chlorine in sewage effluent at pH 8.5. Chlorine dioxide was also found to be a more stable bactericide in relation to pH in the range studied.
Article
BENARDE,MELVINA. (Rutgers, TheStateUniversity, New Brunswick, N.J.), BERNARDM. ISRAEL, VINCENTP.OLIVIERI, AND MARVINL.GRANSTROM.Efficiency of chlorine dioxide as a bactericide. Appl.Microbiol. 13:776-780. 1965-Wefoundchlorine dioxide tobea more effective disinfectant thanchlorine insewage effluent atpH 8.5. Chlorine dioxide was alsofoundtobea more stable bactericide inrelation topH inthe rangestudied.
Article
The trihalomethane (THM) yield on a total organic carbon (TOC) basis was measured as a function of the molecular weight of precursor organics in the Iowa River. Gel permeation chromatography with Sephadex G-75 gel was utilized to separate naturally occurring organics into apparent molecular weight fractions that were subsequently chlorinated to 2 mg/L of free residual and analyzed for THMs. Ninety percent of the organics in the Iowa River were of mol wt less than 3000, while 75% of the THMs were derived from the mol wt less than 3000 fraction. It was found that bromoform was derived from only the smallest organics of mol wt less than 1700.
Article
This study was conducted to examine the effects of chlorine dioxide on dehydrogenase enzymes, protein synthesis, and deoxyribonucleic acid of bacteria in order to elucidate the mode of action of chlorine dioxide. Experiments were carried out in a specially designed unit which permitted sampling for bacterial survivals at time intervals from 5 to 1800 s after the addition of the disinfectant. Bacterial numbers were determined by the pour plate technique. The total dehydrogenase activity of Escherichia coli was determined by the colorimetric estimation of triphenyl formazan, and cell extracts were assayed for their ability to incorporate radioactive phenylalanine into protein. DNA extracted from chlorine dioxide-treated Haemophilus influenzae was tested for its ability to transform competent cells. Partially purified DNA was also exposed to chlorine dioxide and tested for transformability.
Article
During 1974 in the West Midlands of England, 38% of children less than 6 years old with enteritis were excreting rotaviruses. Children aged from 6 months to 3 years were those most commonly infected. Rotavirus infections were most common during winter with only a few sporadic cases during summer. A possible pathogen was detected in 59% of patients examined.
Article
The inactivation of simian rotavirus SA-11 and human rotavirus type 2 (Wa) by ozone was compared at 4 degrees C by using single-particle virus stocks. Although the human strain was clearly more sensitive, both virus types were rapidly inactivated by ozone concentrations of 0.25 mg/liter or greater at all pH levels tested. Comparison of the virucidal activity of ozone with that of chlorine in identical experiments indicated little significant difference in rotavirus-inactivating efficiencies when the disinfectants were used at concentrations of 0.25 mg/liter or greater.
Article
The inactivation of simian rotavirus SA-11 and human rotavirus type 2 (Wa) by chlorine was compared at 4 degrees C by using single-particle virus stocks. Both virus types were usually more readily inactivated at pH 6.0 than at pH 8.0 when low chlorine concentrations (0.05 to 0.2 mg/liter) were used. A complete (5 log) reduction of both was obtained within 20 s at all pH levels when chlorine concentrations were increased to 0.3 mg/liter. Slight differences in the chlorine sensitivities of SA-11 and human rotavirus type 2 were noted but were not considered to be significant.
Article
We found chlorine dioxide to be a more effective disinfectant than chlorine in sewage effluent at pH 8.5. Chlorine dioxide was also found to be a more stable bactericide in relation to pH in the range studied.
Article
The kinetics of inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine were studied at 5 degrees C with a purified preparation of single virions and a preparation of cell-associated virions. Inactivation of the virus preparations with chlorine and chlorine dioxide was studied at pH 6 and 10. The monochloramine studies were done at pH 8. With 0.5 mg of chlorine per liter at pH 6, more than 4 logs (99.99%) of the single virions were inactivated in less than 15 s. Both virus preparations were inactivated more rapidly at pH 6 than at pH 10. With chlorine dioxide, however, the opposite was true. Both virus preparations were inactivated more rapidly at pH 10 than at pH 6. With 0.5 mg of chlorine dioxide per liter at pH 10, more than 4 logs of the single-virus preparation were inactivated in less than 15 s. The cell-associated virus was more resistant to inactivation by the three disinfectants than was the preparation of single virions. Chlorine and chlorine dioxide, each at a concentration of 0.5 mg/liter and at pH 6 and 10, respectively, inactivated 99% of both virus preparations within 4 min. Monochloramine at a concentration of 10 mg/liter and at pH 8 required more than 6 h for the same amount of inactivation.
Article
During two epidemics of acute diarrhoea in China in late 1982/early 1983, more than 12 000 adults in two coal mining districts were affected. The virus isolated from stool samples resembled a rotavirus morphologically. Antigenically it lacked the group antigen shared by known rotaviruses. Like other rotaviruses it had a double-stranded RNA with 11 discrete segments, but the pattern of migration of the segments on polyacrylamide electrophoresis differed from those of other rotaviruses.
Article
92 cases of acute gastroenteritis were registered among 256 individuals during an outbreak in a nursing home for the elderly, the majority of patients being between 70 and 90 years of age. Most cases appeared in 4 of the 8 wards; 66% of the inmates of these wards became ill. Characteristic symptoms were initial nausea and vomiting followed by diarrhoea and low fever. A number of patients were severely ill. One patient died. Rotavirus infection was diagnosed by virus detection and/or antibody titre rise during the acute phase of the illness in 13 of 16 patients examined. At the end of the outbreak, high titres of complement-fixing antibodies against rotavirus (greater than or equal to 64) were detected in serum from 21/22 patients convalescing from the disease, as compared to only 5/45 individuals with no signs of disease. It is tentatively suggested that the outbreak became extensive and rather severe because of lowered immunity against rotavirus infection among the elderly.
Article
Chlorine dioxide and iodine inactivated poliovirus more efficiently at pH 10.0 than at pH 6.0. Sedimentation analyses of viruses inactivated by chlorine dioxide and iodine at pH 10.9 showed that viral RNA separated from the capsids, resulting in the conversion of virions from 156S structures to 80S particles. The RNAs release from both chlorine dioxide- and iodine-inactivated viruses cosedimented with intact 35S viral RNA. Both chlorine dioxide and iodine reacted with the capsid proteins of poliovirus and changed the pI from pH 7.0 to pH 5.8. However, the mechanisms of inactivation of poliovirus by chlorine dioxide and iodine were found to differ. Iodine inactivated viruses by impairing their ability to adsorb to HeLa cells, whereas chlorine dioxide-inactivated viruses showed a reduced incorporation of [14C]uridine into new viral RNA. We concluded, then, that chlorine dioxide inactivated poliovirus by reacting with the viral RNA and impairing the ability of the viral genome to act as a template for RNA synthesis.
Article
The Rotavirus genus of the Reoviridae consists of a number of antigenically related and morphologically identical viruses that cause enteritis, primarily in young mammals and avians. The genus was established by the International Committee on Taxonomy of Viruses at the Fourth International Congress for Virology in 1978 (Matthews 1979). Type species, such as human and bovine rotavirus, have been proposed, but because there are multiple serotypes and cross-infection of heterologous species may occur these names may be difficult to formalize. It is clear that an acceptable nomenclature for rotavirus species is needed.
Article
We prospectively evaluated infections with several gastrointestinal pathogens in patients undergoing bone-marrow transplantation, in an attempt to correlate infection with morbidity and mortality. Thirty-one of 78 patients (40 per cent) were infected with one or more of the following enteric pathogens during the study: adenovirus (12 infections), rotavirus (nine), coxsackievirus (four), or Clostridium difficile (12). Several patients were infected with more than one pathogen. Infection correlated with the occurrence of diarrhea and abdominal cramps. The mortality rate among the infected patients was 55 per cent--significantly higher than the rate (13 per cent) among the noninfected patients (P less than 0.001). This study indicates that enteric pathogens that often cause mild diarrhea in normal populations can cause serious infections in marrow-transplant recipients. Measures aimed at preventing or treating such infections might reduce the morbidity and mortality associated with marrow transplantation.
Article
An outbreak of diarrhoea caused by rotavirus is described. Eleven patients and four staff on the cardiology ward were affected. Rotavirus was detected in five of 11 individuals examined (45 per cent) and rising antibody was demonstrated by immune electron microscopy. Our findings indicate that adults, over 60 years of age in particular, may be susceptible to rotavirus when exposed in confined communities.
  • R R Sokal
  • F J Rohif
Sokal, R. R., and F. J. Rohif. 1969. Biometry. W.H. Freeman & Co., San Francisco.