Inactivation of coliphage MS-2 and poliovirus by copper, silver, and chlorine

1992 ◽  
Vol 38 (5) ◽  
pp. 430-435 ◽  
Author(s):  
Moyasar T. Yahya ◽  
Timothy M. Straub ◽  
Charles P. Gerba
Keyword(s):  
Key Words ◽  
Enteric Viruses ◽  
Silver Ions ◽  
Water Systems ◽  
Free Chlorine ◽  
Inactivation Rate ◽  
Swimming Pools ◽  
Poliovirus Type ◽  
Test Systems

The efficacy of electrolytically generated copper and silver ions (400 and 40 μg/L, respectively) was evaluated separately and in combination with free chlorine (0.2 and 0.3 mg/L) for the inactivation of coliphage MS-2 and poliovirus type 1 in water at pH 7.3. The inactivation rate was calculated as log10 reduction/min: k = −(log10Ct/C0)/t. The inactivation of both viruses was at least 100 times slower in water containing 400 and 40 μg/L copper and silver, respectively (k = 0.023 and 0.0006 for MS-2 and poliovirus, respectively), compared with water containing 0.3 mg/L free chlorine (k = 4.88 and 0.036). Significant increases in the inactivation rates of both viruses were observed in test systems containing 400 and 40 μg/L copper and silver, respectively, with 0.3 mg/L free chlorine when compared with the water systems containing either metals or free chlorine alone. Poliovirus was approximately 10 times more resistant to the disinfectants than coliphage MS-2. This observation suggests either a synergistic or an additive effect between the metals and chlorine for inactivation of enteric viruses. Use of copper and silver ions in water systems currently used in swimming pools and spas may provide an alternative to high levels of chlorination. Key words: enteric viruses, poliovirus, coliphage MS-2, bacteriophage, disinfection, inactivation, copper, silver, chlorine.

Disinfection of bacteria in water systems by using electrolytically generated copper:silver and reduced levels of free chlorine

1990 ◽  
Vol 36 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Moyasar T. Yahya ◽  
Lee K. Landeen ◽  
Maria C. Messina ◽  
Susan M. Kutz ◽  
Richard Schulze ◽  
...  
Keyword(s):  
Drinking Water ◽  
Key Words ◽  
Tap Water ◽  
Total Coliform ◽  
Water Systems ◽  
Free Chlorine ◽  
Drinking Water Standards ◽  
Indoor And Outdoor

As an alternative disinfectant to chlorination, electrolytically generated copper:silver (400 and 40 μg/L copper and silver, respectively) with and without free chlorine (0.3 mg/L) was evaluated over a period of 4 weeks in indoor and outdoor water systems (100 L tap water with natural body flora and urine). Numbers of total coliform, pseudomonas, and staphylococci were all less than drinking water standards in systems treated with copper:silver and free chlorine and systems treated with free chlorine alone (1.0 mg/L). No significant differences (p ≤ 0.05) in bacterial numbers were observed between systems with copper:silver and free chlorine and those with free chlorine alone. Overall, free-chlorine treatments (0.3 or 1.0 mg/L) showed significantly lower heterotrophic plate numbers than those without free chlorine. When challenged with a natural Staphylococcus sp. isolate, water with copper:silver and free chlorine had a 2.4 log10 reduction in bacterial numbers within 2 min, while free chlorine alone or copper:silver alone showed 1.5 and 0.03 log10 reductions, respectively. Addition of copper:silver to water systems may allow the concentration of free chlorine to be reduced while still providing comparable sanitary quality of the water. Key words: disinfection, water, copper, silver, chlorine.

Influence of aerobic microorganisms upon virus survival in soil

1988 ◽  
Vol 34 (5) ◽  
pp. 696-699 ◽  
Author(s):  
Christon J. Hurst
Keyword(s):  
Sandy Loam ◽  
Inactivation Rate ◽  
Poliovirus Type ◽  
Soil Desiccation ◽  
Anaerobic Microorganisms ◽  
Comparable Effect ◽  
Loam Soil ◽  
Incubation Temperatures ◽  
Virus Survival

Survival of human poliovirus type 1 in a sandy loam soil appeared to be deleteriously influenced by aerobic microorganisms. This effect was determined by comparing the survival of virus in soil under four different possible combinations of aerobic versus anaerobic (H2–CO2) atmosphere and sterile versus nonsterile condition. Storage of samples was done in humid chambers to prevent soil desiccation. The effect attributed to aerobic microorganisms was measurable and statistically significant at all three incubation temperatures used in the study (1, 23, and 37 °C), with the increase in inactivation rate attributable to aerobic microorganisms generally being two to threefold. No comparable effect was observed to occur for anaerobic microorganisms under the sets of conditions employed in the study.

Disinfection of Human Enteric Viruses in Water by Copper: Silver and Reduced Levels of Chlorine

1993 ◽  
Vol 27 (3-4) ◽  
pp. 351-355 ◽  
Author(s):  
Albert Bosch ◽  
José M. Díez ◽  
F. Xavier Abad
Keyword(s):  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Tap Water ◽  
Silver Ions ◽  
Water Systems ◽  
Free Chlorine ◽  
Viral Pathogens ◽  
Human Rotavirus ◽  
Low Levels ◽  
Total Elimination

Electrolytically generated copper: silver ions were evaluated in combination with low levels of chlorine for their ability to reduce the infectivity of hepatitis A virus, human rotavirus, adenovirus and poliovirus seeded in well and tap water. Overall, hepatitis A virus and rotavirus showed less than 2.6 log10 titre reduction for concentrations of 1 mg/l of free chlorine. For free chlorine concentrations of 0.5 mg/l or lower, with or without copper: silver ions, both of these viral strains suffered little inactivation. Poliovirus showed more than 4 log10 titre reduction in the presence of copper: silver combined with 0.5 mg/l of free chlorine, or 1 mg/l of free chlorine alone. Copper: silver ions (700:70 µg/l) reduced the infectivity of poliovirus. Although adenovirus was more efficiently inactivated than rotavirus or hepatitis A virus, it persisted longer than poliovirus under the same treatments, and its infectivity was never completely removed. The addition of copper: silver ions to reduce the levels of free chlorine do not ensure the total elimination of viral pathogens from water systems.

Microbiological Evaluation of Copper : Silver Disinfection Units for Use in Swimming Pools

1989 ◽  
Vol 21 (3) ◽  
pp. 267-270 ◽  
Author(s):  
Lee K. Landeen ◽  
Moyasar T. Yahya ◽  
Susan M. Kutz ◽  
Charles P. Gerba
Keyword(s):  
Pathogenic Bacteria ◽  
Silver Ions ◽  
Free Chlorine ◽  
Swimming Pools ◽  
Log10 Reduction ◽  
Bactericidal Effects ◽  
Pure Cultures ◽  
Bactericidal Activities ◽  
Low Levels ◽  
Hot Tubs

The bactericidal effects of electrolytically generated copper:silver ions on pathogenic bacteria of concern in swimming pools, hot tubs and cooling towers were evaluated in disinfection experiments. Copper:silver ion concentrations generated in well water were 400:40 µg/L, respectively. Pure cultures of Legionellapneumophila, Staphylococcusaureus, Pseudomonasaeruginosa, Escherichiacoli, and Streptococcusfaecalis, were individually tested in water containing copper:silver ions alone, copper:silver ions with free chlorine, and free chlorine alone. Greater numbers of organisms were killed after exposure to copper: silver ions with 0.2 mg/L free chlorine than in either the copper:silver ions or free chlorine alone. L. pneumophlla showed greater than a 5 log10 reduction in numbers after 7 minutes exposure to copper:silver ions with 0.2 mg/L free chlorine. In comparison, less than a 2 log10 decrease was obtained after exposure to free chlorine alone. E.coli numbers decreased over 4 log10 after 1 minute exposure to copper:silver ions with 0.2 mg/L free chlorine and less than a 3 log10 decrease after exposure to free chlorine alone. The majority of the other organisms tested showed the same effect. Electrolytically generated copper:silver ions with low levels of free chlorine appear to have greater bactericidal activities than either disinfectant alone.

Survie de virus entériques adsorbés sur microfibre de verre au cours d'un transport postal

1981 ◽  
Vol 27 (2) ◽  
pp. 246-248 ◽  
Author(s):  
J. -C. Joret ◽  
J. -C. Block
Keyword(s):  
Control System ◽  
Enteric Viruses ◽  
Qualitative Studies ◽  
Waste Waters ◽  
Solution Ph ◽  
Poliovirus Type ◽  
Extract Solution ◽  
Beef Extract

The survival of enteric viruses (poliovirus type 1, Mahoney strain, and indigenous viruses of waste waters) has been studied after adsorption of the viruses (pH 3.5) on glass microfiber filters.After postal transport, the presence of the viruses was checked on the filters being soaked in a 3% beef extract solution (pH 7.5) either frozen or without protection against heat. Viruses were recovered at a rate of 59 to 65%.For qualitative studies, postal shipment of samples adsorbed on fiberglass may allow extension of a control system for enteroviruses in water. [Journal translation]

Second-step reconcentration of environmental samples by ammonium sulfate flocculation of beef extract

1987 ◽  
Vol 33 (6) ◽  
pp. 571-572 ◽  
Author(s):  
Pierre Payment ◽  
Michel Trudel
Keyword(s):  
Ammonium Sulfate ◽  
Environmental Samples ◽  
Enteric Viruses ◽  
Second Step ◽  
Poliovirus Type ◽  
Beef Extract ◽  
Coxsackievirus B ◽  
Acid Environment

Some enteric viruses are sensitive to the acid environment utilized during the concentration of viruses from water. The use of a neutral flocculant, neutralized ammonium sulfate at 50% saturation, permitted the recovery of 97% of the simian rotavirus SA-11, 87% of Coxsackievirus B-4, and 88% of poliovirus type 1. This method should permit a better recovery of enteric viruses from the environment.

Efficacy of a combined system of copper and silver and free chlorine for inactivation of Naegleria fowleri amoebas in water

1995 ◽  
Vol 31 (5-6) ◽  
pp. 119-122 ◽  
Author(s):  
J. M. Cassells ◽  
M. T. Yahya ◽  
C. P. Gerba ◽  
J. B. Rose
Keyword(s):  
Synergistic Effect ◽  
Exposure Time ◽  
Silver Ions ◽  
Free Chlorine ◽  
Log10 Reduction ◽  
Naegleria Fowleri ◽  
Combined System ◽  
Water Ph ◽  
Nægleria Fowleri ◽  
Time Required

Electrolytically generated copper and silver ions (400:40 and 800:80 μg/l) were evaluated, separately and combined with 1.0 mg/l free chlorine, for their efficacy in reducing the viable numbers of Naegleria fowleri amoebas in water (pH 7.3 and 23-25°C). Inactivation rates (k = log10 reduction/min) and T99 values (exposure time required to achieve a 99% or a 2 log10 reduction) of the disinfectants were determined. Copper and silver alone, at ratio of 400:40 to 800:80 μg/l caused no significant inactivation of N. fowleri even after 72 hours of exposure (k = 0.00017 and 0.00013, respectively). Addition of 1.0 mg/l free chlorine to water which contained 400:40 or 800:80 μg/l copper and silver resulted in enhanced inactivation rates (k = 0.458 and 0.515, respectively) compared to either chlorine alone (k = 0.33) or the metals alone. Water containing 800:80 μg/l copper and silver with 1.0 mg/l chlorine showed a T99 value of 3.9 minutes, while chlorine alone showed a T99 of 6.1 minutes. Enhanced inactivation of N. fowleri by a combined system of free chlorine and copper and silver may be attributed to the different mechanism that each disinfectant utilizes in inactivating the amoebas, and may suggest a synergistic effect.

Correlation of virus polypeptide structure with attenuation of poliovirus type 1.

1977 ◽  
Vol 23 (3) ◽  
pp. 811-815 ◽  
Author(s):  
J B Milstien ◽  
J R Walker ◽  
L J Eron
Keyword(s):  
Poliovirus Type ◽  
Polypeptide Structure
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