The Risk of Cryptosporidium to Sydney's Drinking Water Supply

Cox, Peter; Hawkins, Peter; Warnecke, M.; Ferguson, Christobel; Deere, Daniel; Bustamante, Heriberto; Swanson, P.; Griffith, Merran; Tamsitt, Lynn; Nicholson, Colin

doi:10.1016/b978-044451351-9/50046-x

Cited by 4 publications

(4 citation statements)

References 4 publications

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Section: Introductionmentioning

confidence: 99%

“…In order to protect the quality of Sydney's drinking water, Sydney Water Corporation and the Sydney Catchment Authority (SCA) have adopted a Catchment to Customer risk management approach after the Cryptosporidium water crisis in 1998 (Cox et al 2003). As part of this strategy, risk assessment and risk management of the drinking water supply in relation to Cryptosporidium is based firstly on identifying sources of Cryptosporidium and the types of Cryptosporidium from each source.…”

Section: Introductionmentioning

confidence: 99%

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Genotypes of Cryptosporidium from Sydney water catchment areas

Ryan¹,

Read²,

Hawkins

et al. 2005

J Appl Microbiol

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Aims: Currently cryptosporidiosis represents the major public health concern of water utilities in developed nations and increasingly, new species and genotypes of Cryptosporidium are being identified in which the infectivity for humans is not clear. The complicated epidemiology of Cryptosporidium and the fact that the majority of species and genotypes of Cryptosporidium cannot be distinguished morphologically makes the assessment of public health risk difficult if oocysts are detected in the raw water supplies. The aim of this study was to use molecular tools to identify sources of Cryptosporidium from the Warragamba catchment area of Sydney, Australia. Methods and Results: Both faecal and water samples from the catchment area were collected and screened using immunomagnetic separation (IMS) and immunofluorescence microscopy. Samples that contained Cryptosporidium oocysts were genotyped using sequence and phylogenetic analysis of the 18S rDNA, and the heatshock (HSP-70) gene. Analysis identified five Cryptosporidium species/genotypes including C. parvum (cattle genotype), C. suis, pig genotype II, the cervid genotype and a novel goat genotype. Conclusions: Monitoring and characterization of the sources of oocyst contamination in watersheds will aid in the development and implementation of the most appropriate watershed management policies to protect the public from the risks of waterborne Cryptosporidium. Significance and Impact of the Study: This study has shown that quantification by IMS analysis can be combined with the specificity of genotyping to provide an extremely valuable tool for assessing the human health risks from land use activities in drinking water catchments.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Genotypes of Cryptosporidium from Sydney water catchment areas

Ryan¹,

Read²,

Hawkins

et al. 2005

J Appl Microbiol

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“…A further three simulations of hazardous event impacts on gastrointestinal risk are used to illustrate: 1) complete failure of the WFP during dry weather flows; 2) failure of Lake Burragorang as a barrier, caused by the short circuiting of flood waters comparable to the 1998 incident (e.g. Hawkins et al 2000 andCox et al 2003); and 3) concurrent STP bypass and high short circuiting flows. STP performance data were collected in two ways.…”

Section: Methodsmentioning

confidence: 99%

Estimating the risk from sewage treatment plant effluent in the Sydney catchment area

Akker

Whiffin

Cox

et al. 2011

Water Science and Technology

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This study employed Quantitative Microbial Risk Assessment (QMRA) to estimate the gastrointestinal risks associated with Cryptosporidium and Giardia discharged from three STPs located within the Lake Burragorang catchment. The QMRA considered baseline and various hazardous event scenarios (e.g. plant failure and heavy rainfall). Under baseline conditions, the combined effect of constructed barriers, catchment barriers and dilution reduced pathogen numbers from the discharge of all three STPs by 10 to 14 orders of magnitude. This was sufficient for the risk to be well below currently mooted benchmarks of 'tolerable risk', even when relatively conservative assumptions were applied. For all hazardous event scenarios, the level of risk remained low, which illustrated the benefit of multiple barriers. Provisionally it appears that the STPs currently discharging into the waterways of the catchment do not pose an unacceptable or unmanageable risk to Sydney's drinking water consumers.Key words 9 9 9 9 Cryptosporidium, drinking water catchment, Giardia, risk assessment, sewage

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“…In the United States, a series of regulations under the Safe Drinking Water Act ( U.S. Environmental Protection Agency 1998 ) required the monitoring and removal of Cryptosporidium in response to a series of waterborne cryptosporidiosis outbreaks, including the largest ever recorded, with an estimated 400,000 cases [ MacKenzie et al 1994 ; possibly overestimated through self-reporting bias ( Hunter and Syed 2001 )]. In Sydney, Australia, a series of boil water advisories in 1998 followed high-level Cryptosporidium detections in the city’s water supply ( Cox et al 2003 ). Although no cases of illness were associated with the incident, the Australian water industry responded by voluntarily adopting externally audited risk management systems based on hazard analysis and critical control points (HACCP) ( Deere and Davison 1998 ; Havelaar 1994 ).…”

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confidence: 99%

Meeting Report: Application of Genotyping Methods to Assess Risks from Cryptosporidium in Watersheds

Ferguson

Deere²,

Sinclair

et al. 2006

Environ Health Perspect

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A workshop titled “Application of Genotyping Methods to Assess Pathogen Risks from Cryptosporidium in Drinking Water Catchments” was held at the International Water Association biennial conference, Marrakech, Morocco, 23 September 2004. The workshop presented and discussed the findings of an interlaboratory trial that compared methods for genotyping Cryptosporidium oocysts isolated from feces. The primary goal of the trial and workshop was to assess the utility of current Cryptosporidium genotyping methods for determining the public health significance of oocysts isolated from feces in potable-water–supply watersheds. An expert panel of 16 watershed managers, public health practitioners, and molecular parasitologists was assembled for the workshop. A subordinate goal of the workshop was to educate watershed management and public health practitioners. An open invitation was extended to all conference delegates to attend the workshop, which drew approximately 50 interested delegates. In this report we summarize the peer consensus emerging from the workshop. Recommendations on the use of current methods by watershed managers and public health practitioners were proposed. Importantly, all the methods that were reported in the trial were mutually supporting and found to be valuable and worthy of further utility and development. Where there were choices as to which method to apply, the small-subunit ribosomal RNA gene was considered to be the optimum genetic locus to target. The single-strand conformational polymorphism method was considered potentially the most valuable for discriminating to the subtype level and where a large number of samples were to be analyzed. A research agenda for protozoan geneticists was proposed to improve the utility of methods into the future. Standardization of methods and nomenclature was promoted.

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The Risk of Cryptosporidium to Sydney's Drinking Water Supply

Cited by 4 publications

References 4 publications

Genotypes of Cryptosporidium from Sydney water catchment areas

Genotypes of Cryptosporidium from Sydney water catchment areas

Estimating the risk from sewage treatment plant effluent in the Sydney catchment area

Meeting Report: Application of Genotyping Methods to Assess Risks from Cryptosporidium in Watersheds

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