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New research articles

Subject: New research articles
From: Muruleedhara Byappanahali <byappan@usgs.gov>
Date: Fri, 24 Nov 2006 11:45:55 -0600
Delivered-to: beachnet-archive@glc.org
Delivered-to: beachnet@great-lakes.net

fyi...

J Water Health 04 (2006) 417-424

A case–cohort study to investigate concomitant waterborne outbreaks of Campylobacter and gastroenteritis in Söderhamn, Sweden, 2002–3
Stephen Martin, P. Penttinen, M. Ljungström, G. Allestam, Y. Andersson, J. Giesecke and G. Hedin

European Programme for Intervention Epidemiology Training (EPIET) and Department of Epidemiology, Swedish Institute For Infectious Disease Control, SE – 171 82, Solna, Sweden, Tel.: +46 8457 2392, Fax: +46 8 30 06 26, s.martin@doctors.org.uk

Department of Epidemiology, Swedish Institute For Infectious Disease Control, SE – 171 82, Solna, Sweden

County Medical Office Gävleborg,County Medical Office, Gävle Hospital, SE – 801 87, Gävle, Sweden

ABSTRACT
Increased domestic, laboratory confirmed, Campylobacter notifications were reported in Söderhamn municipality, December 2002 and January 2003. Concurrently, during preliminary investigations a large outbreak of acute gastroenteritis was detected. Simultaneously, two studies were completed to identify risk factors for infection with Campylobacter and acute gastrointestinal infection (AGI): (1) a case–cohort study using Campylobacter cases (N =101) with a large random sample from the municipal population as referents (N=1000) and (2) a retrospective cohort study for the outcome AGI using the same sample. A postal questionnaire was used to collect demographic, clinical, water and food consumption data. Measures of association (risk ratio (RR), odds ratio (OR)) and 95% confidence intervals (CI) were calculated. Stool, environmental and water samples were tested by standard methods at Gävle Hospital and SMI laboratories respectively. In the case–cohort study, Camplylobacter cases were more likely than referents to consume communal water (OR=12.6 (95% CI 1.7–92.3)). In the cohort study, risk of gastroenteritis was 2.3 times higher in those who consumed water (AR=27.3%) than others (AR=12%). Risk of illness was associated with the amount of water consumed in both studies. Campylobacter was detected in stools and Escherichia coli (E. coli) from routine communal water (CW) samples. Results suggest both Söderhamn outbreaks of Campylobacter and AGI were associated with consumption of CW. The method used strengthened epidemiological evidence and was efficient in the use of time and resources.

Keywords: case–cohort study, concommitant water-borne outbreaks

J Water Health 04 (2006) 425-430

Water ingestion during swimming activities in a pool: A pilot study
Alfred P. Dufour, Otis Evans, Thomas D. Behymer and Ricardo Cantú

US Environmental Protection Agency, National Exposure Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA, Tel.: +1 (513) 569-7330, Fax: +1 (513) 569-7464, dufour.alfred@epa.gov

Lilly Research Laboratories,A Division of Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, 46285,USA

ABSTRACT
Chloroisocyanurates are commonly added to outdoor swimming pools to stabilize chlorine disinfectants. The chloroisocyanurates decompose slowly to release chlorine and cyanuric acid. Studies conducted to determine if the chloroisocyanurates might be toxic to swimmers showed that they were not and that ingested cyanuric acid passed through the body unmetabolized. This fact was used to determine the amount of water swallowed during swimming activity. Fifty-three recreational swimmers, using a community swimming pool disinfected with cyanuric acid stabilized chlorine, participated in the study. The participants did not swim on the day before or after the test swim. The swimmers were asked to actively swim for at least 45 minutes and to collect their urine for the next 24 hours. Cyanuric acid was measured in pool water using high performance liquid chromatography and porous graphitic carbon columns with UV detection. The urine sample assay required a clean-up procedure to remove urinary proteins and interfering substances. Results of the study indicate that non-adults ingest about twice as much water as adults during swimming activity. The average amount of water swallowed by non-adults and adults was 37 ml and 16 ml, respectively. The design for this study and the analytical methodology used to assay cyanuric acid in swimming pool water and human urine were effective for measuring the volume of water swallowed during swimming activity.

Keywords: cyanuric acid, swimming, water, water ingestion

J Water Health 04 (2006) 437-452

Occurrence of Cryptosporidium oocysts in US wastewaters
Randi M. McCuin and Jennifer L. Clancy

Clancy Environmental Consultants, Inc., PO Box 314, Saint Albans,VT, 05478, USA, Tel.: +1 (802) 527-2460, Fax: +1 (802) 524-3909, jclancy@clancyenv.com rmccuin@clancyenv.com

ABSTRACT
Wastewater samples collected from ten wastewater facilities across the US were analyzed to determine the occurrence of indigenous Cryptosporidium oocysts using methods based on modifications of USEPA Method 1622. Wastewater facilities participating in this study ranged in size from 0.6 to 193 mgd average daily flow. A total of 289 wastewater samples were analyzed over a 15-month period. ColorSeed is a commercial product containing gamma-irradiated Cryptosporidium oocysts that have been permanently stained with a Texas Red dye. ColorSeed was used as an internal control with each sample to assess method performance. In 500 ml sample volumes, mean ColorSeed recoveries in raw influents and primary effluents were 26.1±17.7% and 33.0±17.9%, respectively. In 10 liter volumes of secondary effluent, mean ColorSeed recovery was 25.0±16.6%. Volumes analyzed for tertiary effluent samples ranged from 14.8 l to 131.3 l resulting in a mean ColorSeed recovery of 48.8±14.5%. Indigenous oocysts were detected in 30% of raw influents, 46% of primary effluents, 58% of secondary effluents and 19% of tertiary effluents analyzed. Indigenous oocyst concentrations ranged from <2 to 86 /liter across all wastewater matrices tested.

Keywords: ColorSeed,Cryptosporidium,detection,methods,occurrence,wastewater

J Water Health 04 (2006) 479-486

Application of microbial risk assessment on a residentially-operated Bio-toilet
Naoko Nakagawa, Masahiro Otaki, Hana Oe and Katsuyoshi Ishizaki

Dept. of Human Environmental Sciences, Ochanomizu Univ., 2-1-1 Otsuka, Bunkyo-ku, 112-8610, Tokyo, Japan, Tel.: +81-3-59785748, Fax: +81-3-59782049, urbanoasis@pop11.odn.ne.jp

Graduate School of Frontier Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-0033, Tokyo, Japan

Research Institute for a Sustainable Future, Waseda University, 513 Tsurumaki-chou,Waseda, Shinjuku-Ku, Tokyo, 169-8050,Japan

ABSTRACT
The Sustainable Sanitation System is a new wastewater treatment system that incorporates a non-flushing toilet (Bio-toilet) that converts excreta into a reusable resource (as fertilizer or humus for organic agriculture) and reduces the pollution load to environments of the rivers, the lakes, and the sea. However, the risk of exposure to pathogens should be considered, because excrement is stored in the Bio-toilet. The aim of the present work is to analyze the health risk of dealing with the matrix (excreta and urine mixed with sawdust) of the Bio-toilet. Therefore, the fate of pathogenic viruses was investigated using coliphages as a virus index, and the modeling of the die-off rate in matrix was introduced. Then the microbial risk assessment was applied to a Bio-toilet that was actually used in a residential house; the infection risks of rotavirus and enterovirus as reference pathogens were calculated. According to the lab-scale experiment using coliphages for investing the die-off rate of viruses in the Bio-toilet, Qβ had a higher die-off, which was greatly influenced by the water content and temperature. On the other hand, T4 showed a lower rate and was independent of water content. Therefore, these two phages' data were used as critical examples, such as viruses having high or low possibilities of remaining in the Bio-toilet during the risk assessment analysis. As the result of the risk assessment, the storage time required for an acceptable infectious risk level has wide variations in both rotavirus and enterovirus cases depending on the phage that was used. These were 0–260 days' and 0–160 days' difference, respectively.

Keywords: Bio-toilet, die-off rate, microbial risk assessment, sustainable sanitation system

J Water Health 04 (2006) 487-498

Quantitative detection of E. coli, E. coli O157 and other shiga toxin producing E. coli in water samples using a culture method combined with real-time PCR
Leo Heijnen and Gertjan Medema

Kiwa Water Research, PO Box 1072, 3430 BB, Nieuwegein, The Netherlands, Tel.: +31 306 069743, Leo.Heijnen@Kiwa.NL

ABSTRACT
Recent water related outbreaks of shiga toxin producing E. coli O157 have resulted in increased attention of the water industry to this potentially deadly pathogen. Current methods to detect E. coli O157 and its virulence genes are laborious and time-consuming. Specificity, sensitivity and simple use of a real-time PCR method makes it an attractive alternative for the detection of STEC E. coli O157. This study describes the development and application of real-time PCR methods for the detection of E. coli O157, shiga toxin genes (Stx1 and Stx2) and E. coli. The specificity of the methods was confirmed by performing colony-PCR assays on characterized bacterial isolates, demonstrating the applicability of these assays as rapid tests to confirm the presence of E. coli or E. coli O157 colonies on culture plates. Sensitive culture-PCR methods were developed by combining culture enrichment with real-time PCR detection. This rapid method allowed detection of low concentrations of E. coli O157 in the presence of high concentrations of non-O157-E. coli (1:10⁴). Culture-PCR methods were applied to 27 surface water and 4 wastewater samples. E. coli O157 and both Stx genes were detected in two wastewater samples, whereas only E. coli O157 was detected in two surface water samples. Culture-PCR methods were not influenced by matrix effects and also enabled quantitative (MPN) detection of E. coli in these samples.

Keywords: environment,Escherichia coli,O157,real-time PCR,Stx,water

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Murulee Byappanahalli, Ph. D.
Research Microbiologist
U.S. Geological Survey, Great Lakes Science Center
Lake Michigan Ecological Research Station,
1100 N. Mineral Springs Road
Porter, Indiana 46304
Phone: (219) 926-8336 ext. 421
Fax: (219) 929-5792
E-mail: byappan@usgs.gov

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