C Gerba

Publications of C Gerba

• Microbial risk assessment for recreational use of the Chicago area waterway system.

  Authors: G Rijal, J K Tolson, C Petropoulou, T C Granato, A Glymph, C Gerba, M F Deflaun, C O'Connor, L Kollias, R Lanyon

  Journal of water and health. 03/2011; 9(1):169-86.

  A microbial risk assessment was conducted to estimate the human health risks from incidental contact recreational activities such as canoeing, boating and fishing in the Chicago Area Waterway SystemA microbial risk assessment was conducted to estimate the human health risks from incidental contact recreational activities such as canoeing, boating and fishing in the Chicago Area Waterway System (CAWS) receiving secondary treated, but non-disinfected, effluent from three municipal water reclamation plants. Actual concentrations of the pathogens (pathogenic E. coli [estimated], Giardia, Cryptosporidium, adenovirus, norovirus, enteric virus) detected from the waterway field data collection at locations upstream and downstream of the effluent outfall during dry and wet weather conditions within the recreation season were included in the risk assessment. The results under the current treatment scheme with no disinfection indicated that the total expected gastrointestinal illness (GI) rate per 1000 incidental contact recreational exposure events during combined weather (dry and wet) conditions ranged from 0.10 to 2.78 in the CAWS, which is below the eight illnesses per 1000 swimmers considered tolerable by the United States Environmental Protection Agency. Wet weather conditions contribute to elevated pathogen load to the CAWS; therefore this study determined that disinfecting the effluents of three major WRPs that discharge to the CAWS would result in an extremely small reduction in the aggregate recreation season risk to incidental contact recreators.

• Dry and wet weather microbial characterization of the Chicago area waterway system.

  Authors: G Rijal, C Petropoulou, J K Tolson, M Deflaun, C Gerba, R Gore, T Glymph, T Granato, C O'Connor, L Kollias, R Lanyon

  Water science and technology : a journal of the International Association on Water Pollution Research. 01/2009; 60(7):1847-55.

  The Chicago Area Waterway System (CAWS) is a man-made channel, which serves the Chicago area for the drainage of urban storm water and the conveyance of secondary treated effluent from theThe Chicago Area Waterway System (CAWS) is a man-made channel, which serves the Chicago area for the drainage of urban storm water and the conveyance of secondary treated effluent from the Metropolitan Water Reclamation District of Greater Chicago's (District) North Side, Stickney and Calumet water reclamation plants (WRPs). A microbial characterization of the CAWS upstream and downstream of the WRPs and from the WRP outfall was initiated by collecting dry and wet weather samples and analyzing for indicators and pathogens. During dry weather, indicator bacteria (fecal coliform [FC], E. coli [EC], enterococci [EN]) were the most abundant microbial species detected in the CAWS compared to pathogens (Salmonella spp [SA], enteric viruses [EV], adenovirus [AV], norovirus [NV] and Giardia and Cryptosporidium). Pseudomonas aeruginosa [PA] levels in the outfall samples were either lower or equivalent to the CAWS. The wet weather samples had a higher frequency of detection of indicator bacteria and pathogens compared to dry weather samples. Overall, the concentrations of pathogens in the CAWS, representing the weather conditions experienced in a recreational year, were relatively low. The study concluded that the presence of pathogens in the CAWS downstream of the WRPs were due to secondary loading of the waterway under wet weather conditions from combined sewer overflows (CSOs) and other discharges.

• Role of irrigation and wastewater reuse: comparison of subsurface irrigation and furrow irrigation.

  Authors: C Choi, I Song, S Stine, J Pimentel, C Gerba

  Water science and technology : a journal of the International Association on Water Pollution Research. 02/2004; 50(2):61-8.

  Two different irrigation systems, subsurface drip irrigation and furrow irrigation, are tested to investigate the level of viral contamination and survival when tertiary effluent is used in arid andTwo different irrigation systems, subsurface drip irrigation and furrow irrigation, are tested to investigate the level of viral contamination and survival when tertiary effluent is used in arid and semi-arid regions. The effluent was injected with bacteriophages of PRD1 and MS2. A greater number of PRD1 and MS2 were recovered from the lettuce in the subsurface drip-irrigated plots as compared to those in the furrow-irrigated plots. Shallow drip tape installation and preferential water paths through cracks on the soil surface appeared to be the main causes of high viral contamination in subsurface drip irrigation plots, which led to the direct contact of the lettuce stems with the irrigation water which penetrated the soil surface. The water use efficiency of the subsurface drip irrigation system was higher than that of the furrow irrigation system. Thus, subsurface drip irrigation is an efficient irrigation method for vegetable crops in arid and semi-arid regions if viral contamination can be reduced. Deeper installation of drip tapes, frequent irrigations, and timely harvests based on cumulative heat units may further reduce health risks by ensuring viral die-off under various field conditions.

• Rapid reduction of Legionella pneumophila on stainless steel with zeolite coatings containing silver and zinc ions.

  Authors: P Rusin, K Bright, C Gerba

  Letters in applied microbiology. 02/2003; 36(2):69-72.

  AIMS: To determine the rate of reduction of Legionella pneumophila by stainless steel surfaces with zeolite ceramic coatings containing 2.5% (w/w) silver (Ag) and 14% zinc (Zn) ions. METHODS ANDAIMS: To determine the rate of reduction of Legionella pneumophila by stainless steel surfaces with zeolite ceramic coatings containing 2.5% (w/w) silver (Ag) and 14% zinc (Zn) ions. METHODS AND RESULTS: Stainless steel pans with and without Ag/Zn coatings were inoculated with solutions of Leg. pneumophila ATCC 33155 and incubated at 37 degrees C. Survival was monitored using the spread-plate technique on selective buffered charcoal yeast extract agar. Significant reductions of Leg. pneumophila were effected by the Ag/Zn zeolite coatings within 2 h of exposure. CONCLUSIONS, Significance and Impact of the Study: Zeolite ceramic Ag/Zn coatings impart significant anti-Legionella properties to stainless steel surfaces. Coated stainless steel could be used in the manufacture of air ducts, condensation pans and intake and exhaust vents. These products have the potential to reduce numbers of Legionella in air-handling systems.

• Comparative surface-to-hand and fingertip-to-mouth transfer efficiency of gram-positive bacteria, gram-negative bacteria, and phage.

  Authors: P Rusin, S Maxwell, C Gerba

  Journal of applied microbiology. 01/2002; 93(4):585-92.

  AIMS: To determine the transfer efficiency of micro-organisms from fomites to hands and the subsequent transfer from the fingertip to the lip. METHODS AND RESULTS: Volunteers hands were sampled afterAIMS: To determine the transfer efficiency of micro-organisms from fomites to hands and the subsequent transfer from the fingertip to the lip. METHODS AND RESULTS: Volunteers hands were sampled after the normal usage of fomites seeded with a pooled culture of a Gram-positive bacterium (Micrococcus luteus), a Gram-negative bacterium (Serratia rubidea) and phage PRD-1 (Period A). Activities included wringing out a dishcloth/sponge, turning on/off a kitchen faucet, cutting up a carrot, making hamburger patties, holding a phone receiver, and removing laundry from the washing machine. Transfer efficiencies were 38.47% to 65.80% and 27.59% to 40.03% for the phone receiver and faucet, respectively. Transfer efficiencies from porous fomites were <0.01%. In most cases, M.luteus was transferred most efficiently, followed by phage PRD-1 and S. rubidea. When the volunteers' fingertips were inoculated with the pooled organisms and held to the lip area (Period B), transfer rates of 40.99%, 33.97%, and 33.90% occurred with M. luteus, S. rubidea, and PRD-1, respectively. CONCLUSIONS: The highest bacteral transfer rates from fomites to the hands were seen with the hard, non-porous surfaces. Even with low transfer rates, the numbers of bacteria transferred to the hands were still high (up to 10(6) cells). Transfer of bacteria from the fingertip to the lip is similar to that observed from hard surfaces to hands. SIGNIFICANCE AND IMPACT OF THE STUDY: Infectious doses of pathogens may be transferred to the mouth after handling an everyday contaminated household object.

• Secondary wastewater disposal for crop irrigation with minimal risks.

  Authors: G Oron, R Armon, R Mandelbaum, Y Manor, C Campos, L Gillerman, M Salgot, C Gerba, I Klein, C Enriquez

  Water science and technology : a journal of the International Association on Water Pollution Research. 02/2001; 43(10):139-46.

  A critical objective for any wastewater reuse program is to close the gap between supply of and demand for water and to minimize health and environmental hazards. Thus, the effects of treatedA critical objective for any wastewater reuse program is to close the gap between supply of and demand for water and to minimize health and environmental hazards. Thus, the effects of treated effluent on crops, soils and community health must be considered carefully. When applying wastewater to soil-plant systems, it is to be noted that the passage of water through the soil reduces considerably the number of microorganisms carried out by the reclaimed wastewater. Nevertheless, there is a need to study the real rate of organism decay subject to water quality, soil and vegetable characteristics, and irrigation method. The aim of this work is to determine the fate of the fecal coliforms, coliphages F+ and CN13, and helminth eggs survival during the application of reclaimed wastewater in a vineyard orchard near the City of Arad (Israel) via onsurface and subsurface drip irrigation systems. Wastewater obtained from a stabilization pond, and soil samples were tested and an important decrease of microorganisms was reached in both cases, with the better values obtained with the sub-surface drip irrigation system.

• Reduction of faecal coliform, coliform and heterotrophic plate count bacteria in the household kitchen and bathroom by disinfection with hypochlorite cleaners.

  Authors: P Rusin, P Orosz-Coughlin, C Gerba

  Journal of applied microbiology. 12/1998; 85(5):819-28.

  Fourteen sites evenly divided between the household kitchen and bathroom were monitored on a weekly basis for numbers of faecal coliforms, total coliforms and heterotrophic plate count bacteria. TheFourteen sites evenly divided between the household kitchen and bathroom were monitored on a weekly basis for numbers of faecal coliforms, total coliforms and heterotrophic plate count bacteria. The first 10 weeks comprised the control period, hypochlorite cleaning products were introduced into the household during the second 10 weeks, and a strict cleaning regimen using hypochlorite products was implemented during the last 10 weeks. The kitchen was more heavily contaminated than the bathroom, with the toilet seat being the least contaminated site. The highest concentrations of all three classes of bacteria were found on sites that were moist environments and/or were frequently touched; these included the sponge/dishcloth, the kitchen sink drain area, the bath sink drain area, and the kitchen faucet handle(s). The implementation of a cleaning regimen with common household hypochlorite products resulted in the significant reduction of all three classes of bacteria at these four sites and other household sites.

• Risk assessment of virus in drinking water.

  Authors: C N Haas, J B Rose, C Gerba, S Regli

  Risk analysis : an official publication of the Society for Risk Analysis. 11/1993; 13(5):545-52.

  The reevaluation of drinking water treatment practices in a desire to minimize the formation of disinfection byproducts while assuring minimum levels of public health protection against infectiousThe reevaluation of drinking water treatment practices in a desire to minimize the formation of disinfection byproducts while assuring minimum levels of public health protection against infectious organisms has caused it to become necessary to consider the problem of estimation of risks posed from exposure to low levels of microorganisms, such as virus or protozoans, found in treated drinking water. This paper outlines a methodology based on risk assessment principles to approach the problem. The methodology is validated by comparison with results obtained in a prospective epidemiological study. It is feasible to produce both point and interval estimates of infection, illness and perhaps mortality by this methodology. Areas of uncertainty which require future data are indicated.

• Application of Gene Probes to Poliovirus and Hepatitis A Virus Detection in Water and Shellfish

  Authors: A. Margolin, M. Bitrick, R. DeLeon, C. Gerba

  OCEANS '87; 10/1987

  Viral gastroenteritis and hepatitis A virus transmission by shellfish continues to occur in the United States. Current methods for the detection of enteric viruses in cell culture take several daysViral gastroenteritis and hepatitis A virus transmission by shellfish continues to occur in the United States. Current methods for the detection of enteric viruses in cell culture take several days to weeks.Many rapid techniques such as immunoassays (i.e. enzyme-linked-immuno assay) lack the needed sensitivity for the detection of low numbers of viruses likely to be present in shellfish. Recently we have developed cDNA probes for poliovirus type 1 and hepatitis A virus labeled with both 32p dATP and dCTP which are capable of detecting as little as one fg of nucleic acid or one tissue culture infectious dose of poliovirus type 1 or one radio-immunofocus unit of hepatitis A virus. Results are obtained within 72 hours as cell culture is not necessary.We have successfully applied this method to the detection of enteroviruses in both water and shellfish concentrates.

• Risk Assessment of Enteric Virus Disease Transmission by Shellfish Consumption

  Authors: C. Gerba, S. Goyal

  OCEANS; 10/1987

  Densely populated coastal regions of the world generate large quantities of domestic sewage and sludge which is often disposed into the marine environment. Present in these wastes are humanDensely populated coastal regions of the world generate large quantities of domestic sewage and sludge which is often disposed into the marine environment. Present in these wastes are human pathogenic viruses which are capable of surviving for prolonged periods of time in the marine environment and transmitting disease to humans. Hepatitis A virus and Norwalk virus outbreaks associated with shellfish consumption continue to occur in the United States. Three separate epidemiological studies have also shown an epidemiological association between shellfish consumption and increased risk of hepatitis A infection in consumers. An epidemiological association between non-A and non-B hepatitis has also been demonstrated. A review of the risks of infection, clinical illness and mortality associated with enteroviruses suggest that the present of these viruses in shellfish presents a significant risk to the consumer.