Program 1 Newsletter - Issue 15 - September 1999
In this Issue:
New Research Project
    A system for the early detection of outbreaks of water-related gastroenteritis for Australia
Arsenic in Bangladesh
Cryptosporidium Laws Introduced
Sydney - One Year Later
Water Advice Revised
E. coli Outbreak at US County Fair
Cause of UK Outbreak Unknown
Microbial Threats to Water
CRCWQT Scholarships
News Items
From the Literature
Contact Information
New Research Project

A system for the early detection of outbreaks of water-related gastroenteritis for Australia
Project Leader - Assoc Prof Kit Fairley

Current methods for the surveillance of waterborne diseases, and gastrointestinal diseases in general, are acknowledged to be relatively insensitive and slow since they rely mainly on laboratory identification of pathogens and subsequent notification to health authorities. Such methods detect only the "tip of the iceberg" in terms of illness in the community, as less than 10% of people with gastroenteritis attend a doctor, and perhaps only 10% of these have a faecal specimen tested for pathogens.

Relatively large outbreaks of disease could be missed by current surveillance systems, and the usual time lag of two weeks or more between the causative event and recognition of an outbreak by health authorities limits the usefulness of response measures.

Retrospective analysis of outbreaks, including the Milwaukee Cryptosporidium outbreak in 1993, have pointed to several options for increasing the speed and sensitivity of surveillance. A Melbourne Water/ CRCWQT funded feasibility study by Dr Alex Padiglione confirmed that a number of existing data sources had the potential to form the basis of a greatly improved surveillance system for waterborne diseases in Australia (1).

Work in this area is now being continued by PhD student Dr Jim Black at the Department of Epidemiology and Preventive Medicine at Monash University. This project is developing artifical neural networks to analyse health related and water quality data to detect and predict outbreaks. Staff from the Department of Human Services Victoria are also involved in the project, and will collaborate on pilot testing the program.

Most artificial neural networks are clever pieces of computer software that can ‘learn’ to recognise patterns in a suitable data set. They are already in use in many and diverse fields, cleaning electrical noise out of ECG signals, predicting electric load requirements in UK cities, and even letting your personal computer ‘understand’ spoken words. But so far their use has not been much explored in the field of water quality and health.

The appeal of artificial neural networks is that they can often recognise relationships within a data set that are too subtle for a human observer to detect. They are intrinsically non-linear in nature, so they stand up well against the standard statistical methods (though many would say that some types of network are really just a new twist on non-linear regression models). So if faecal coliform counts go up only on dry Sunday afternoons three weeks after rainy Saturday mornings in May, a neural network has a fair chance of finding that out. Or they may be able to ‘see’ patterns in the number of requests for faecal specimen analysis that indicate a growing outbreak long before any of the microbiology results come back from the lab.

This research project is developing just such potential uses for artificial neural networks. Neural networks are straightforward in theory but challenging in practical implementation, but after several months of program development in C++ language the basic neural network program is now becoming a viable proposition. The next stage is to gather some apparently disparate data sets from the water industry, the health service, the Bureau of Meteorology and others, and start building the neural models.

The project also involves the development of other computing tools to analyse and present data in an easily accessible form to water authorities and health agencies. One such component, called MapMovie, is a tool that allows for rapid scanning of both the spatial and temporal relationships in a database, by rapidly re-drawing a map several times per second on a computer screen. The result is a ‘movie’ of the development of an outbreak or other event throughout the study area over time. A cut-down version of MapMovie has been developed to analyse the evolution of vaccination coverage by local government area, and will soon be field tested by DHS. Mechanisms for the automatic acquistion of pathology laboratory results and numbers of faecal specimen requests by DHS are also being developed. In the future, such health inputs will be linked with water quality figures and Geographic Information Systems to create an integrated set of programs capable of detecting outbreaks at the earliest possible stage, and determining whether they are related to drinking water supplies.

1) Padiglione A and Fairley CK (1998). “Early detection of outbreaks of waterborne gastroenteritis.” Water 25(6): 11-15.

Arsenic in Bangladesh

CRCWQT researchers Dr Wayne Smith, Dr Bruce Caldwell and Dr Tony Adams, Prof Robert Douglas (NCEPH, Australian National University) and Assoc Prof Malcolm Sim (DEPM, Monash University) have been awarded an AusAID grant to conduct research on arsenic contamination of tubewells in Bangladesh.

The project will be carried out in collaboration with Dr Jack Ng from the National Research Centre for Environmental Toxicology in Brisbane, and staff from the International Centre for Diarrhoeal Disease Research in Bangladesh. The problem of arsenic contamination of tubewells in many areas of Bangladesh was first recognised in 1993, and it is apparent that some of the population are suffering serious health effects as a consequence of long term exposure to arsenic in groundwater supplies.

Ironically, many of these tubewells were contructed by international aid agencies in a bid to supply the population with microbiologically safe groundwater as an alternative to contaminated surface water supplies. Diarrhoeal diseases, often transmitted by faecally contaminated water supplies, are major causes of illness and child mortality in Bangladesh.

It is estimated that up to 95% of the population of 130 million may currently use the arsenic contaminated wells as their primary source of drinking water, posing major public health problems which are rendered more complex by the lack of resources in this densely populated developing nation. Following discovery of the problem, the World Bank together with AusAID and a range of other international aid agencies has initiated a number of projects to help characterise and ameliorate the problem.

Prolonged exposure to high levels of arsenic is known to cause characteristic skin lesions and skin cancers (arsenicosis) and arsenic has been implicated in increased risks of a range of internal cancers. Chronic arsenic poisoning can affect several organ systems, causing gastrointestinal disturbances, anaemia, and damage to the peripheral nervous system, liver, kidneys and heart. However there is a lack of good quality epidemiological data on individual exposure and specific health effects, and the consequences of long term population or individual exposures cannot be predicted with any certainty.

Arsenic in food may make a significant contribution to the total body burden, and the chemical form of arsenic (inorganic vs organic) has an effect on metabolism and toxicity. Adverse health effects of arsenic exposure have most commonly been observed in poor populations, but rarely in more affluent groups with the same apparent exposure levels, and it has been suggested that nutritional deficiences may play a role in exacerbating the toxic effects of arsenic.

This project, which will also be supported by CRCWQT funding, will comprise a pilot study of arsenic health effects and measures of exposure, and a survey of current practices and social attitudes to potential measures to reduce arsenic exposure. The study will be facilitated by existing linkages between researchers, and an established network of field stations and ICDDR personnel experienced in epidemiological studies in Bangladesh.

Factors to be determined in the social survey will include the level of community knowledge of arsenic contamination in the water supply, patterns of household water usage, and demographic and economic data. The health effects study will test the use of photography to grade and diagnose skin lesions, determine the feasibility and variability of urinary arsenic measurements, and the feasibility of assessing the contribution of food to total arsenic exposure.

The pilot project will take about 12 months to complete, and is expected to lay the groundwork for development of a range of specific intervention studies in collaboration with Bangladesh authorities.

Cryptosporidium Laws Introduced

On 30 June 1999 the British government began implementation of new regulations (1) which will require many water sources to be continuously monitored every day for Cryptosporidium oocysts. As reported in Health Stream Issue 11, the regulations will impose a mandatory average limit of 1 oocyst/10 litres of finished water. Water utilities which exceed this limit will be guilty of a criminal offence, and may be subject to prosecution and financial penalties, even if there is no evidence of a waterborne disease outbreak.

Under the regulations, water treatment plants have essentially been classified into 3 groups:

(a) Water supplies which are treated by a process capable of continuously removing or retaining particles greater than 1 micron diameter, and with stringent process monitoring and failure controls, will be exempt from the requirement to monitor for Cryptosporidium oocysts.

(b) Water supplies with any of the following characteristics will be required to implement monitoring for Cryptosporidium oocysts:
(c) All other water supplies are to be subjected to a risk assessment process to determine whether there is a "significant risk" of Cryptosporium oocysts in drinking water.

As the first step in implementation, water companies in England and Wales will be required to deliver risk assessment reports for all of their water treatment plants to the Secretary of State by 1 October 1999. Risk assessments are to be done according to a framework established by the Drinking Water Inspectorate. The company must include an "Assessment Conclusion" stating whether or not it believes there is a significant risk of Cryptosporidium oocysts in water from each plant. For the purposes of the regulation, a "significant risk" equates to the presence of an average of 1 or more oocysts per 10 litres of water at any time with sampling and analysis according to the regulations.

Within 1 month of receiving the reports, the DWI will notify each company whether the risk assessments are considered satisfactory, or whether further assessments are required. Where the risk assessment is deemed satisfactory, and the company has concluded that a significant risk exists, the company will be requested to nominate the earliest practicable date when monitoring could commence at each site. The water company has 3 months to respond to this request. Monitoring at the highest priority sites is expected to commence by April 2000.

The regulations require continuous sampling of water leaving the treatment plant at a rate of at least 40 litres per hour, with an interuption of 1 hour being allowed each day for replacement of the sampling device. There are also prescriptive procedures for water sampling, transport of samples and laboratory testing.

In order to maintain an unbroken "chain of evidence" which is admissible in court, strict security measures and documentation procedures are required at all stages, although a proposed requirement to videotape the microscopic enumeration of oocysts has been dropped. Personnel and laboratories carrying out the tests must be approved by the DWI, and will be subject to periodic proficiency testing.

The enumeration procedure involves counting three classes of Cryptosporidium oocysts (those with typical internal structure, those with amorphous internal structure, and those which are empty) however all are combined to give the figure for reporting under the regulations. Under normal circumstances the samples are to be analysed within 3 days of collection, however if a significant increase in turbidity is observed, or any other indication that oocyst numbers in finished water may have increased (eg coagulation problems), the sample must be analysed within 24 hours.

Tests with an average of 0.7 oocysts or more per 10 litres of water, or those where identification of microorganisms is unclear must be checked by an analyst from an another approved laboratory. All slides must be preserved for 3 months, and slides with samples exceeding the prescribed concentration must be stored indefinitely.

In its May 1998 dicussion paper, the DWI estimated that 121 plants treating surface water would be subject to the regulations and that ongoing costs would total about £8 million per year. However as the scope of the regulations has now been expanded to cover many more water sources, the monitoring and testing costs will have risen proportionately. For example, a large English water company which expected to monitor 5% of its water treatment plants under the original proposals now estimates that about 25% of plants will be affected, with monitoring costs up to 5 times the original estimate.

1) The Water Supply (Water Quality) (Amendment) Regulations. Statutory Instruments 1999 No.1524.

Documents relating to the regulations can be obtained from the DWI internet site:
www.dwi.detr.gov.uk/h2oinfo.htm

 Sydney - One Year Later

The first anniversary of the Sydney water contamination incidents was marked by a number of newspaper articles in the Sydney Morning Herald about the impact of the events, and the changes that have occurred in the interim.

On 26 July a front page article, " Water cleanup nobbled ", reported that the NSW state government planned to divert a large portion of the funds raised by the newly established Sydney Catchment Authority (SCA) into other areas, leaving only a small amount for catchment improvement programs.

Bulk water sales by the SCA are expected to generate an income of about $119 million per year, however about $45 million will be used by the government to repay Sydney Water loans, and to provide additional funding for schools, roads and the police force. Much of the remainder is required for the operational expenses of the SCA, with some estimates that as little as $2 million will be available for catchment improvement. The SCA has disputed this figure, saying available funding will be substantially higher.

Critics have charged that underfunding of the SCA will lead to perpetuation of the catchment management problems that were identified by the McClellan Inquiry (1), and have questioned the government's commitment to fully implement the recommendations of the Inquiry.

Among the changes in the year since the water contamination incidents occurred are:

The regulatory powers of the SCA have not yet been determined, and will depend heavily on the outcome of a Regional Environmental Plan which is expected to be finalised next year. Environmental groups have called for strong planning powers to be vested in the catchment authority to ensure that it can veto development proposals which threaten water quality.

A separate inquiry by the Independent Regulatory Tribunal will set public healthand environmental objectives as part of the first five year operating licence for the SCA.

Another major recommendation of the Sydney Water Inquiry was the establishment of an independent laboratory for Cryptosporidium and Giardia testing. At present, water testing is performed by Sydney Water's own laboratory (Australian Water Technologies Pty Ltd). In early August the NSW Health Department issued a call for Expressions of Interest in establishing a new laboratory, and an invitation for Tenders is expected in the next few months. Only a handful of laboratories in Australia have substantial experience with advanced testing methods for Cryptosporidium and Giardia, and as yet none of these methods has been NATA accredited.

Due to the lack of proven testing methods for reliable detection of human infectious protozoa, no Guideline values for Cryptosporidium or Giardia have been set in the current Australian Drinking Water Guidelines (1996), and none have been recommended during the recent revision of Fact Sheets for these microorganisms by an expert working party. This is in keeping with the stance adopted by other countries such as the US and Canada, and reflects the inability to set a health based limit for exposure to these microorganisms. The UK stands alone as being the only nation to impose numerical limits for Cryptosporidium oocyst levels in drinking water, and this limit is not based on health criteria (see p3 this issue).

1) Sydney Water Inquiry - Final Report. December 1998. Peter McClellan QC. See Health Stream Issue 13 for summary.

Water Advice Revised

The UK expert group on Cryptosporidium in Water Supplies has issued revised advice to the immunocompromised. In its report delivered in late 1998 (1), the group used a broad definition of "immunocompromised" to include all HIV infected people, people on chemotherapy for cancer treatment, organ transplant recipients taking anti-rejection drugs, and those with genetic disorders of the immune system.

People in these groups were advised to boil all water before consumption (including tap and bottled water, and water used to make ice) as a precaution against Cryptosporidium infection.

The definition of "immunocompromised" people has now been made much narrower and recognises the importance of T-cell deficiences in Cryptosporidium infection (2). This particular class of white blood cells play an important role in the immune system's ability to combat this protozoan pathogen, and people with very low T-cell numbers are at risk of suffering prolonged illness with severe symptoms if they become infected with Cryptosporidium parvum .

The revised advice now applies only to people whose T-cell function is impaired, including a subgroup of HIV infected people (those with AIDS and low T-cell count), children with the condition severe combined immunodeficiency (SCID), and people with specific T-cell deficiencies. The change has been welcomed by the medical community as giving a more accurate recognition of the high risk groups, and providing reassurance to a broader range of people who may have been unnecessarily alarmed by the previous advice.

1) Cryptosporidium in Water Supplies. Third Report of the Group of Experts. Department of the Environment, Transport and the Regions and Department of Health (1998).

2) Cryptosporidium in Water: clarification of the advice to the immunocompromised. Chief Medical Officer's Update 23 August 1999, Department of Health, London.

E. coli outbreak at US County Fair

Unchlorinated water from a contaminated well has been identified as the probable source of a large E. coli O157:H7 outbreak in New York State. The well was one of several used to supply water to the Washington County Fair from 23-29 August. The fair was attended by over 100,000 people, and more than 921 cases of suspected E. coli infection have been reported to health authorities. Officials expect the final figure may exceed 1,000 cases, making this one of the largest outbreaks ever recorded for this pathogen.

In contrast to the harmless E. coli strains normally found in the intestine of humans and warm blooded animals, the O157:H7 strain produces a potent toxin (vero toxin) which causes cell damage, leading to the development of bloody diarrhoea (haemorrhagic colitis). The infection may also result in severe dehydration and kidney damage requiring dialysis treatment (Haemolytic Uremic Syndrome). Fatalities may occur particularly among young children and the elderly. In the current outbreak, two fatalities were reported up to 17 September, with about 60 people hospitalised and several in serious condition.

Water from the contaminated well was used by six booths at the fair for preparing food and beverages for sale to visitors. At least two vendors are believed to have used stored water from this source for a subsequent event at a different venue. The well was reportedly clear of faecal contamination when tested in June, but may have been subsequently contaminated by seepage from nearby dairy farms after heavy rain.

E. coli infections, mainly from unchlorinated drinking water supplies, recreational water, contaminated meats and unpasteurised milk, are believed to be responsible for about 20,000 cases of illness and 400 deaths each year in the US. In the wake of this outbreak, New York State officials are now said to be considering new regulations governing water supplies for state fairs and other large public events.

Cause of UK Outbreak Unknown

Investigators of the Cryptosporidium outbreak which affected north west England in May and June have been unable to identify a specific event which led to contamination of the water supply with oocysts (Health Stream Issue 14 p9). Over a period of 1 month, more than 360 laboratory confirmed cases of crytosporidiosis occurred in four health authority districts affected by the outbreak, with the number of epidemiologically linked clinical cases expected to be considerably larger. Genetic typing of oocysts has shown they are of "genotype 2" which readily infects humans and other mammals.

The catchment for the Thirlmere reservoir is about 11,000 acres with the predominant land uses being low density sheep farming and forestry. Some of the sheep grazing in the catchment were carrying Cryptosporidium, but they were not scouring and had not begun lambing when the water contamination was detected. The animals were excluded from the surrounds of the reservoir by a perimeter wall, and weather conditions were not unusual.

The water source is considered high quality and water treatment consists of microstraining (pore size >20 microns - not capable of removing oocysts), chlorination and pH adjustment. Tests for Cryptosporidium and Giardia in raw water have been carried out at roughly weekly intervals for several years. Most results have been negative with about 6% of 10 litre samples containing 1 or 2 oocysts, and one sample in late 1997 with 4 oocysts. No increases in illness were associated with these oocyst detections. The sample which sparked the alert for this outbreak contained 34 oocysts in 10 litres, but there were no other indications of water quality problems.

Water from the Thirlmere source is blended with several other supplies, and therefore may reach as many as 1.5 million consumers. Contamination of the aqueduct which carries the treated water to a number of distribution points has not been ruled out as a cause of the outbreak.

Microbial Threats to Water

The American Society for Microbiology has released an issues paper calling for a greater emphasis on microbial pollutants in the management of US water supplies (1). The report contends that despite recent changes in legislation and new regulatory inititiatives, the major focus of US EPA water policy remains on toxic chemical pollutants.

The authors of the report, who include several prominent experts in quantitative microbial risk assessment, call for better integration of regulatory responsibilities and greater emphasis on rigorous risk assessment for biological, chemical and physical threats to water quality.

The report calls for establishment of a joint task force of the EPA, CDC, the National Institute for Environmental Health Sciences and other federal agencies to:

Recommendations are also made for an independent scientific assessment of the microbial safety of US water supplies in order to:

1) Microbial Pollutants in Our Nation's Water. American Society for Microbiology:
   www.asmusa.org/pasrc/reports.htm

CRCQWT Scholarships

Postgraduate Scholarships The CRC for Water Quality and Treatment is offering five Postgraduate Scholarships for students wishing to undertake PhD studies commencing in 2000. A range of projects relating to drinking water quality and treatment are available. Closing date 29 October 1999.

Summer Scholarships The CRC for Water Quality and Treatment provides up to 12 Summer Research Scholarships of approximately 10 weeks duration, between November 1999 and March 2000. Applicants should currently be completing third or fourth year degree programs. Closing date 15 October 1999.

Enquiries should be directed to:
Associate Professor Dennis Mulcahy
Education and Training Program Coordinator
CRC for Water Quality and Treatment
University of South Australia
The Levels Campus, Mawson Lakes, SA 5095
Telephone (08) 8302 3149
Facsimile (08) 8302 3668

Details of Postgraduate and Summer Scholarships are also posted on this site under Education & Training.
News Items

Australian Drinking Water Guidelines

The Rolling Review process of the ADWG is continuing with the release in August for public comment of draft Fact Sheets for Cryptosporidium and Giardia. Revised draft Fact Sheets for several other parameters and a guideline for Microcystin toxin are expected in the next few months.

Parameters to be considered in this years review will comprise Arsenic, Aluminium, Coliforms, Copper, Pseudomonas, Taste and Odour, Turbidity, Water Quality Management. Updates on the progress of the review can be found on the CRCWQT web page:
    www.med.monash.edu.au/epidemiology/crc

For further information see the NHMRC web site:
    www.health.gov.au/nhmrc/advice/contents.htm

NSW Copper Corrosion Report

The NSW Department of Land and Water Conservation recently completed a report on copper corrosion in country water supplies. The report discusses the results of a survey of rural councils on the extent of corrosion problems and identifies short-term management strategies for a variety of circumstances.

The main outcomes of this preliminary survey included:

  • 30 % of the respondents reported some form of copper corrosion;
  • Corrosion indices indicated that about 60 % of the respondents had potentially corrosive waters;
  • 56 % of the respondents with relatively low alkalinity water reported corrosion problems.
Monitoring requirements and approaches for defining specific problems are summarised in the report, and the applicability and costs of various management strategies are reviewed.

Inquiries about the report should be directed to Pradeep Kumar on 02-9895 5951 (phone) or 02-9895 5967 (fax) or pkumar@dlwc.nsw.gov.au (Email)

New Crypto types in HIV infected people

Researchers from the Centers for Disease Control and Prevention have identified Cryptosporidium isolates in some HIV infected patients which are usually associated with cats and dogs. Genotyping of isolates from 10 patients showed 6 people had been infected by genotype 1 (human type), 1 person by genotype 2 (bovine type), 1 person by a canine type and 2 people by the feline type.

This is the first report of these genotypes in humans, and it is not known whether the feline and canine isolates may also infect people with healthy immune systems.

Pieniazek NJ et al. (1999) Emerging Infectious Diseases 5 (3).

Taps run dry in Kent

The UK Deputy Prime Minister met personally with two water company chiefs in August, following an incident where 3,600 households were left without water for up to 4 days. Mid Kent Water was said to have offered a "bewildering list of excuses" to customers including an air blockage, burst main, blown valve, unexpected hot weather and overuse of supplies by consumers. The Office for Water is investigating the incident, and domestic customers are expected to receive £50 in compensation with business losses to be assessed separately.

Moon probe fails to find water

Scientists were unable to detect the hoped-for signs of water when the Lunar Prospector probe crashed into the Moon's surface on 31 July. Telescopes could not locate a visible dust or vapour plume but data analysis continues in the hope that evidence of water may be uncovered.

The Lunar Prospector crash has the distinction of being the first "funeral" on the Moon - the probe carried the ashes of Dr Eugene Shoemaker, a planetary geologist and NASA researcher who was killed in a car accident in 1997.

Fluoridation laws for UK?

The British government is considering news laws to give local councils the power to compel water fluoridation. No new fluoridation schemes have been introduced in Britain since 1985, although over 50 councils have asked water companies to undertake fluoridation. The privatised water industry is reluctant to comply with such requests because of vocal opposition from lobby groups.

Following a recent White Paper on public health, the government will commission a review on the health effects of fluoridation, and if the outcome is favourable will provide local councils with the power to require fluoridation. The decision on fluoridation may be determined by a local referendum in each council district.

Water reduces labour pains

Injections of salt-free water into the lower back have been shown to reduce labour pains. Swedish researchers randomised 99 women into 3 groups - 33 women received 4 subcutaneous injections of water during labour, 33 received intracutaneous water, and 33 received isotonic saline solution. Both groups receiving water reported a significant reduction in labour pains, while the saline group reported a slight reduction.

The reason for the effect if not understood, and the women reported that both subcutaneous and intracutaneous injections were equally painful.

Bottled water risky say Ophthalmologists

Ophthalmologists from the Baylor Medical College in Texas have warned wearers not to use bottled water for washing contact lenses. The researchers said that many consumers believed bottled water was cleaner or safer than tap water, or even assumed it was sterile. However, half of the brands tested contained bacteria or fungi which may pose a risk of eye infections. Only sterile solutions should be used for washing and storage of contact lenses.

Penland RL and Wilhelmus KR (1999) Ophthalmology 106 1500-1503.

US choses Arsenic detection limit

The US EPA has announced a Practicable Quantitation Limit of 3 microgram/ml has been set for arsenic in water. Deliberations on setting a new arsenic limit for drinking water are continuing with the decision due to be announced by January 2000.
Contact Information
Editor - Martha Sinclair email martha.sinclair@med.monash.edu.au
Assistant Editor - Pam Lightbody email pam.lightbody@med.monash.edu.au

The printed version of Health Stream is available free of charge - to be added to our mailing list please contact Pam Lightbody (email above or fax + 61 3 9903 0576). Past issues can be found under Publications.