is waterborne disease a myth?

INFORMATION AND ANALYSIS FOR WATER AND HEALTH PROFESSIONALS

Issue 4 Public Health Newsletter of the CRC for Water Quality and Treatment December 1996

In this Issue: Is waterborne disease a myth? 1 Cryptosporidium makes headlines in Sydney 2 US litigation over Information Collection Rule 3 Workshop Report 4 Micro & Ultrafiltration in Water Treatment Epidemiology Spot 6 The Placebo Effect From the Literature 7 Program 1 Personnel 10 From the Literature (continued) 12 Water quality Cryptosporidium Cyanobacteria E.coli Helicobacter pylori Hepatitis Legionnaire’s disease Aluminium Arsenic Copper Detection methods Risk Assessment List of Articles 18 Forthcoming Meetings 20

Editor Martha Sinclair

Assistant Editor Pam Lightbody

CRCWQT Internet address:

http://www.waterquality.crc.org.au/

Is waterborne disease a myth? The importance of infectious diseases as a major preventable cause of death, particularly in the developing world, is confirmed by the figures contained in the World Health Report 1996: Fighting disease, fostering development.

The report released by the World Health Organisation in May this year, estimated that of the 51.9 million worldwide deaths in 1995, about 17.3 million (33%) were due to infectious diseases. In this group of diseases, about 22% (3.75 million deaths) were due to food, water and soil borne agents. Diarrhoeal illnesses excluding cholera predominated with about 3.1 million deaths, followed by neonatal tetanus (459,000 deaths), hookworm (65,000 deaths) and roundworm infections (60,000 deaths). According to officially reported figures only 11,000 deaths were due to cholera, however the WHO estimates the true figure is about 120,000 deaths.

The report contained some important statements on the relevance of drinking water in the transmission of diarrhoeal diseases. For many years it has been widely accepted that contaminated water is the major vehicle for transmission, and this has led to a predominant emphasis on the microbiological quality of drinking water. However, more recent work by the WHO and others has shown that foodborne transmission is more important and probably accounts for 70% of diarrhoeal episodes.

Bacterial contamination of weaning foods with pathogenic E. coli, Camplyobacter and Shigella is thought to cause up to half of all infant diarrhoeal episodes, and contributes heavily to infant mortality in developing countries.

These changes in thinking about the transmission of so-called “waterborne diseases” were explored in an article in the July 1996 issue of Water and Environment where writer RAJ Arthur discussed

HEALTH STREAM December 1996 PAGE 1

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COOPERATIVE RESEARCH CENTRE FOR WATER QUALITY AND TREATMENT

the World Health Report and the United Nations Habitat II conference with researcher Dr Sandy Cairncross of the London School of Hygeine and Tropical Medicine. Dr Cairncross has worked extensively in Africa in a WHO program to eliminate dranunculitis (Guinea worm disease). He pointed out that while waterborne transmission was clearly the cause of many epidemics of cholera and typhoid, sound epidemiological evidence was lacking to link water with other causative agents of diarrhoeal disease. This is particularly true of endemic diseases in developing nations.

It is now apparent that endemic transmission of enteric infections probably occurs mainly via contaminated food, hands, clothing and other household objects. The shortage of water for washing may have more impact on transmission than the microbiological quality of the water. In this context, there is increasing interest in the reuse of waste water for irrigation to release precious supplies of potable water for drinking and hygeine.

Simple intervention studies in developing countries have shown that diarrhoeal illness in communities can be greatly reduced by encouraging hand washing with soap before preparing meals and after defecation, indicating that basic hygeine and supply of sufficient quantities of water were important factors. Thus it appears that past emphasis on the microbiological quality of drinking water to the virtual exclusion of these other factors may have been inappropriate in public health programs.

Cryptosporidium makes headlines in Sydney

The potential health threats of Cryptosporidium in Sydney's drinking water were the subject of a number of articles in the Sydney Morning Herald in October. The articles, by Science and Environment writer Bob Beale, comprised a page one feature on October 22nd and follow up articles on the 23rd and 24th October.

The stories were based on a draft version of report prepared for Sydney Water Corporation by its

commercial research arm Australian Water Technologies (a member of the CRCWQT). The report was released to the Sydney Morning Herald by Sydney Water Corporation after a copy had been obtained by writer and consumer advocate John Archer under a Freedom of Information application. The draft report is undergoing peer review and the final version is expected to be delivered to Sydney Water in a few weeks.

The first article entitled "Deadly bug threat to tap water" outlined the results of an eight month monitoring program of Sydneys raw and finished water supplies undertaken in 1993 (prior to commissioning of filtration plants). Although Cryptosporidium oocysts were detected only once during this period, the concentration was high in the single positive sample (5,866 oocysts per 10 litres of raw water). The article also quoted a microbiologist as saying that studies suggest that even 1 oocyst may be sufficient to cause infection.

The next article on the topic "Bottled water may not protect against bug" noted that bottled water was not necessarily free of Cryptosporidium, depending on the source and the method of treatment before bottling. This piece also noted that many of the domestic water filters currently sold in Australia did not remove Cryptosporidium.

The report on 24th October focussed on the Potts Hill reservoir, a 800 million litre holding reservoir which serves the eastern side of Sydney. This uncovered reservoir is downstream of the Prospect filtration plant and thus presents an opportunity for recontamination of the filtered water prior to distribution. Although the reservoir has no fish, aquatic plants or other food sources for birds, it is sometimes used by water birds which may be a source of feacal contamination. The article did not state that Cryptosporidium species which infect birds have little if any ability to infect humans, although it is possible that oocysts of mammalian origin may survive passage through avian hosts if ingested.

It should be noted that the detection method used for these surveys did not allow determination of the viability of the oocysts, and if the proportion of



viable oocysts was low the health risk would be substantially reduced. Also, the monoclonal antibody used to label oocysts prior to flow cytometry detection is known to crossreact with species other than C. parvum. Recent work1 on commercially available immunofluorescence kits has shown that a “false positive” rate of up to 35% may occur with Cryptosporidium oocysts which are not C. parvum. Of the several recognised species of Cryptosporidium only C. parvum is considered to constitute a risk to human health.

The AWT researchers used spiking experiments to compare 3 different methods of recovering Cryptosporidium oocysts and Giardia cysts from water samples, and concluded that the ASTM P229 protocol gave the poorest results for both test organisms. The tests on water samples from the Sydney water supply system were therefore carried out using a calcium flocculation - centrifugation procedure followed by immunofluorescence flow cytometry. The spiking tests indicated the recovery yield of this process was up to 30x more efficient than the ASTM method which has been used in most published studies, therefore it is difficult to compare the oocyst/cyst numbers detected by the two different techniques.

The human volunteer experiments conducted by Dupont et al.2 tend to suggest that infection from a single oocyst would be a rare event - of 5 volunteers who ingested 30 viable C. parvum oocysts, only 1 became infected and this person did not actually develop symptoms.

There is justifiable concern over the threat of Cryptosporidium infection in immuno-compromised persons, however it should be noted that immune status does not appear to significantly influence the risk of infection but rather affects the outcome of infection. Data from waterborne outbreaks of cryptosporidiosis indicate that immunocompromised people (people with HIV/AIDS, those receiving cancer therapy, organ and bone marrow transplant recipients, people with congenital immune deficiencies) are not at increased risk of acquiring

cryptosporidiosis but are at greater risk of suffering prolonged and severe infection3.

These articles highlight the difficulties of water authorities and health departments worldwide in dealing with public concern over the health risks of Cryptosporidium in drinking water. While documented outbreaks in a number of cities overseas clearly demonstrate significant health risks when major contamination occurs, current detection methods lack both the sensitivity and specificity to allow clear assessment of risks in nonoutbreak situations. To assess risks to public health we need to know not merely “is there Cryptosporidium in the water?” but “is it Cryptosporidium parvum? and is it viable?” Hopefully new detection methods under development in Australia and elsewhere will soon allow these questions to be answered.

1 Evaluation of a commercial enzyme immunoassay (EIA) and immunofluorescent antibody (IFA) test kits for the detection of Cryptosporidium oocysts of species other than Cryptosporidium parvum. Graczyk, TK, Cranfield MR and Fayer R (1996). Am J Trop-Med-Hyg 54 p274-279. (Summarised in this issue - see From the Literature section).

2 The infectivity of Cryptosporidium parvum in healthy volunteers. DuPont HL, Chappell CL, Sterling CR, Okhuysen PC, Rose JB and Jakubowski W. New-Eng-J-Med (1996) 332 p855-59.

3 Assessing the public health risk associated with waterborne cryptosporidiosis: report of a workshop. Morbidity and Mortality Weekly Report, June 1995, 44 No. RR-6, Centres for Disease Control.

US litigation over Information Collection Rule It was reported in the October 7th edition of Environment Week that continuing court action against the US EPA by the American Water Works Association may delay the development of rules to limit disinfection byproducts and microbial contaminants.

The AWWA has taken federal court action against the EPA over the Information Collection Rule which



was issued on May 14th. The ICR compels water authorities to collect and report data on microbial and disinfection byproduct levels in water from early 1997. It is intended that this data will provide the basis for formulating future drinking water regulations in the US.

The AWWA action particularly focuses on the limitations of the ICR methods for the detection and identification of protozoa in water. The prescribed method for detection of Cryptosporidium (immunofluorescence by ASTM P229 protocol) can give false positive results and cannot distinguish betwen viable and inviable oocysts. An evaluation of the accuracy of 12 commercial testing laboratories using blinded spiked samples showed serious deficiences in a number of aspects1. Four laboratories incorrectly identified algal cells as protozoa (false positives), four failed to detect Giardia and 6 failed to detect Cryptosporidium (false negatives). Only 2 laboratories correctly identified both types of protozoa and did not misclassify the algal cells. The standard and detail of written reports of the test results also varied greatly between laboratories.

The AWWA believes that data collected by this technique will inevitably be flawed, and cannot be legitimately used to develop regulations. There is also concern among water authorities that the compulsory public reporting required by the ICR will leave them open to legal action by consumers, even when the scientific evidence of risk to health is uncertain.

The AWWA action also challenges the short time interval provided to implement the required testing programs, and the addition of some testing requirements in the final form of the ICR which were not present in the proposed version on which consultation with stakeholders was based.

The EPA has stated that the litigation may inhibit ICR negotiations between the EPA and the water industry, however the AWWA has countered that it had no choice but to bring action within the mandatory 45 day period allowed after the ICR was

promulgated, to protect the rights of the water utilities to dispute the ICR provisions.

1 Clancy JL, Gollnitz WD and Tabib Z. Commercial labs: how accurate are they? Journal of the AWWA, (1994) Vol 86 (5) p89-97.

Workshop Report

Workshop on Micro & Ultrafiltration in Water Treatment.

Friday 18 October, Melbourne.

The workshop was held at the CSIRO Division of Chemicals and Polymers, Clayton and was attended by approximately 30 people. The presenters had a variety of expertise ranging from researchers to manufacturers and water service providers.

The workshop began with a welcome by Don Bursill (Director, CRCWQT) and an introduction by Tony Priestley (CSIRO Division of Chemicals and Polymers, Deputy Director CRCWQT). The aim of the workshop was to gain more knowledge of Micro and Ultrafiltration and to formulate a draft program of relevant research projects that could be undertaken by the CRC for Water Quality and Treatment.

A technical overview was given by Tony Fane (University of NSW). Tony examined membrane types and listed some strategies and future potential for improvement. He considered applications of membranes which included membrane use in: the desalination process, secondary treatment, the removal of industrial effluents and the reuse of water. Virus removal using Microfiltration and the variables involved such as pressure, bacteria layer and time were covered. Hybrid systems using a membrane plus a biological or chemical process were discussed.

The next section of the workshop consisted of a series of presentations from membrane filtration users and manufacturers. The first speaker was Pierre Alla (Australian Water Services) who discussed the aims and interests of AWS which include providing cost efficient water of the best



quality and using the best combination of treatment processes. He also described AWS interest in reuse of waste water and combined systems.

Dharma Dharmabalan from Barwon Water spoke about Microfiltration at the Meredith Water Treatment Plant. He gave an overview of the plant which has a capacity of 2.5ML/day with further expansion possible, and currently provides for several country communities. He reviewed the strengths and weaknesses of the filtration processes. Strengths included: more compact, lower capital cost, absence of clarifiers, no sandfilters, automatic operations, good particle removal (Giardia and Cryptosporidium), reduced chemical costs (for low colour water) and changes in flow rates do not affect final water quality. Weaknesses included: colour removal-inability without chemicals, poor dissolved compounds removal, problems with disposal of washwater and reject cleaning solution, short filter run times and high volume of washwater, fairly high energy costs, specialist skills needed to trouble shoot problem areas.

The problems of operation and maintenance were highlighted, in particular the increased membrane fouling rate and frequency of chemical cleaning, colour removal targets being hard to meet, the biological instability of the water, no by-pass option during maintenance and retrieval of data for analysis when problems occur. Future work and issues were discussed with suggestions such as the need for pre/post treatment to enhance water quality, installation of dynamic membranes and use of gas for backwashes.

Colin Nash from Memtec provided a manufacturers point of view. He presented Memtec’s research and development targets in which the following points were raised: membrane and membrane systems cost reduction, colour and Total Organic Carbon (TOC) removal with Microfiltration, better understanding of fouling mechanisms and optimising chemical cleaning methods. The strengths and weaknesses of membrane filtration were reviewed. He presented his ‘Dream Membrane’ - this is an ideal membrane which is non fouling, has a TOC and toxin removal

capacity of Nanofiltration, requires no pretreatment, works at Microfiltration differential pressures (ie < 100k pa) and has a sustainable flux rate of >200 L/hr/m² on cold water. As our knowledge of membrane technology increases this “dream membrane” or aspects of it may be possible in the future.

The last speaker in this section was Pradeep Kumar from the NSW Department of Land and Water Conservation. He presented another users viewpoint. Pradeep reviewed the Microfiltration plant at Kangaroo Valley which has a capacity of 0.84 ML/d and has been operational since December 1993. Some features he highlighted about the plant were: the plant reduces turbidity very effectively, it cannot reduce true colour consistently, dissolved iron and manganese cannot be removed without preoxidation, dissolved organic compounds are not effectively removed, faecal coliforms, coliforms and E. coli are effectively removed, recycling of poor quality lagoon supernatant can deteriorate the membrane performance, trans-membrane pressure is unusually high and filtration capacity is now significantly reduced from design specifications. Future strategies were considered for the plant in regard to algal toxin removal, taste and odour control, dissolved organic compound removal, number of backwashes, CIP (Clean In Place) cycles and membrane life and costs of operation and maintenance.

The second half of the day was aimed at considering future research topics. Mary Drikas (AWQC) talked about membrane evaluation for pathogen, organics and toxin removal. Mary discussed research into algal and algagenic products comparing polyvinylidene fluoride Microfiltration membranes with 0.3 µm pores and polyether sulfone Ultrafiltration membranes. The parameters that were investigated were permeate flux, total cell numbers before and after filtration, chlorophyll a and microcystin-LR levels.

Tony Priestley reviewed hybrid systems with coagulation and adsorption. He summarised the performance of Nanofiltration, Ultrafiltration and Microfiltration and their ability to removal dissolved



organics. Ways of converting soluble materials into a particulate form were discussed, approaches including: coagulation with a metal salt, precipitation with a cationic polymer, absorbing with or without a polymer aid on clay or metal oxide and absorbing on powered activated carbon or a finely divided ion-exchange resin.

Tony Fane and Hans Griesser (CSIRO Division of Chemicals and Polymers) concluded the days presentations with a discussion about new membranes and minimising fouling and maximising performance. Tony described what is needed to achieve better system performance including: improved membranes and modules and the optimisation of operating conditions and cleaning strategies. Hans Griesser spoke about his research into membrane fouling with regard to contact lenses and the surface interactions involved. The principals involved here can be related to membrane filtration.

The day concluded with a general discussion of research topics. Suggestions for research included: looking at the causes of membrane fouling, the removal of natural organic matter, hybrid systems and evaluation of some current membrane filtration systems. It was resolved there should be further discussion by CRCWQT partners involved in future research.

Epidemiology Spot The Placebo Effect

The word placebo appears in the Bible in Psalm 116, Verse 9, “placebo domino in regione vivorum” which is translated from the Latin “as I please”. The concept of the placebo and the placebo effect in medicine was first formally discussed in 1945 by Pepper - A Note on Placebo1.

A placebo treatment usually consists of a “dummy” medication or intervention. This intervention can range from the trial participant taking a tablet, to answering a questionnaire, to using a sham water filter (as will be used in the Water Filter Study). The importance of the placebo effect was described by

Beecher who reviewed fifteen studies of placebo use in patients suffering a variety of conditions (cited in 2). Amongst the problems studied were pain after surgery, headache, drug induced mood change, seasickness and the common cold. On average, these symptoms were “satisfactorily relieved” by a placebo treatment in 35% of patients (the range being 15% to 58%)2, 3.

A wide variation in response is not uncommon with placebos. The placebo response can be seen in patients with acute and chronic conditions, its effect can continue after the cessation of “treatment” and a dose response effect can sometimes be seen. Two placebo capsules can have a greater affect on relieving pain than one alone4, 1. The participants perception of the characteristic of the drug preparation can also influence their response. Larger capsules tend to be perceived as stronger, yellow capsules tend to be thought of as stimulants, injections may produce larger effects than do pills4, 5, 2.

The placebo effect is not only seen with medications. Sham surgery and interventions such as sham tooth grinding procedure and sham ultrasonic treatments have also been shown to have a placebo effect2.

Placebos have also been associated with side effects such as nausea, drowsiness and headaches. The overall incidence of adverse events in healthy volunteers during placebo administration was 19%. Placebos may also make pre-existing symptoms worse4, 2.

The participants expectations of the likely success of the treatment or intervention can influence their response, as can their general attitude towards the treatment and the treatment provider, be this attitude positive or negative. This attitude and expectation can make the placebo response greater or it can reduce the response2.



The potential of the placebo effect in a randomised trial is such that it may distort the answer if the participant or those responsible for treatment know what intervention or treatment the person is receiving. This problem can be avoided by making the trial double blind, whereby neither the participant, nor the researcher are aware of what intervention or treatment the participant receives. This removes a potential bias in the study.

For the placebo to be effective in removing participant and observer bias (both conscious and subconscious) it should simulate the true intervention as closely as possible but must not treat the medical condition or alter the status quo.

When measuring the response of an intervention at the end of the study, we generally assess the placebo response and the response of those who received the real intervention, describing the “true response” as the difference between these two groups. Before we assess the placebo effect in a study, factors potentially influencing the placebo effect such as the natural course of an illness, regression towards the mean and unidentified parallel interventions must be considered. These factors can lessen or increase a placebo effect and should be taken into consideration when estimating ing the placebo effect and assessing the actual effect of the real treatment or intervention6.

1. Rosenzweig P, Brohier S, Zipfel A. The placebo effect in healthy volunteers: Influence of experimental conditions on the adverse events profile during phase I studies. Pharmacol Ther 1993;54:578-83.

2. Turner JA, Deyo RA, Loeser JD, Von Korff M, Fordyce WF. The importance of placebo effects in pain treatment and research. JAMA 1994;271(20):1609-14.

3. Fisher RW. Comparison of antipruritic agents administered orally: a double-blind study. JAMA 1968;203(6):130-1.

4. Blackwell B, Bloomfield SS, Buncher CR. Demonstration to medical students of placebo responses and non-drug factors. Lancet 1972;1(June 10):1279-82.

5. Buckalew LW, Coffield KE. An investigation of drug expectancy as a function of capsule color and size and preparation form. J Clin Psychopharm 1982;2(4):245-8.

6. Ernst E, Resch KL. Concept of true and perceived placebo effects. BMJ 1995;311:551-3.

From the Literature Brief Summaries

Water Quality:

Analysis of virulence characteristics of bacteria isolated from bottled, water cooler and tap water.

Edberg SC, Gallo P, Kontnick C. Microbial Ecology in Health and Disease (1996) 9 p67-77.

This paper investigates the properties of HPC (heterotrophic plate count) bacteria in drinking water sources. The authors obtained samples from water coolers (81 samples, from 9 coolers in the USA), bottled water (150 samples, bottled in the USA, Canada and Europe) and tap water (150 samples, from 3 areas of the USA). Aliquots of 1.0 and 0.01 ml from each sample were plated on R2A Difco agar plates and incubated at 37ºC for 3 days, and each distinct colony type was purified separately.

Isolates were identified according to established methods (Bergey's Manual of Systematic Bacteriology), and tested for a number of characteristics believed to be related to virulence. All water samples were also subjected to a total coliform count (by the Colilert method) and tested for the presence of P. aeruginosa. All isolates were also tested for growth on blood agar.

The virulence characteristics of isolates were tested as follows: Enzyme production - production of chondroitinase, coagulase, DNase, elastase, fibrinolysin, gelatinase, haemolysin, hyaluronidase, lecithinase, lipase and proteinase was tested using appropriate media. Acid lability was assessed by testing survival at pH 3.5.



Antibiotic susceptibility was tested by the disc diffusion method. Cytotoxicity analysis - isolates were tested for cytotoxic effects on HEp-2 cell cultures by the US EPA method.

Results - A wide range of bacteria were isolated from the water samples, and about 95% of isolates failed to grow on blood agar. P. aeruginosa was found in low numbers in a few samples of each water type, and coliforms were detected only in 2 bottled water samples. Investigations showed these to originate from a single production line used for bottling both water and milk.

About 20% of isolates from all water types produced proteinase, but production of other enzymes was much less frequent. None of the isolates was found to be acid resistant. About 25% of isolates were sensitive to "natural" antibiotics (native and first generation antibiotics) and 95% were sensitive to "synthetic" antibiotics (synthetic and later generation antibiotics). Cytotoxicity was detected in only 0.2% to 0.3% of all isolates, and in 0.8% of P. aeruginosa isolates.

The authors conclude that "natural aqueous bacteria" do not possess characteristics associated with virulence, and that future revisions in drinking water legislation should not be directed towards the elimination of such bacterial populations, but rather be aimed at preventing exogenous contamination and eliminating specific pathogens.

Drinking water sources, mortality and diarrhoea morbidity among young children in northern Ghana.

Shier RP, Dollimore N, Ross DA, Binka FN, Quigley M, Smith PG. Trop-Med-Int-Health. (1996) 1 p334-41.

In the Upper East Region of Ghana data was collected over a year on sources of drinking water used by approximately 13,000 mothers/guardians of over 20,000 children and on morbidity and mortality experiences of these children. Boreholes were the main source of drinking water although frequency

varied with the seasons. There was some association between reported drinking water source and diarrhoeal morbidity, this appeared to be seasonal. There was no significant association between drinking water source and child mortality.

Water, waste, and well-being: a multicountry study.

Esrey SA. Am-J-Epidemiol. (1996) 143 p608-23.

Data was collected from eight countries in Sub-Saharan Africa, Asia/North Africa and the Americas in the late 1980s, combined and analysed to test whether incremental improvements in water supply and sanitation result in incremental health effects in regard to diarrhoea and nutrition status. Samples from rural and urban areas were analysed separately.

A comparison of optimal (individual household) and intermediate (public well or tap) water supplies with unimproved water conditions was made. For sanitation, the comparison was between flush toilets /water-seal latrines (optimal) and dry latrines (intermediate) were compared with unimproved conditions. A random representative sample of married women age 15-49 years with or without children in all countries were interviewed. Included in the analysis were children 3-36 months old with available weight and height data.

An association was found between incremental benefits in sanitation and less diarrhoea with additional increases in the weights and heights of children. Greater effects of improved sanitation were seen among urban dwellers than among rural dwellers. It was concluded that improved sanitation conferred greater benefits than improved water supplies. Only when sanitation was also improved did the benefits from improved water supply occur and only when optimal water supply was present

Cryptosporidium:

Milwaukee’s crypto outbreak: investigation and recommendations.



Fox KR and Lytle DA. J-AWWA (1996) 88 (9) p87-94.

This is one of several articles in this issue of the Journal of the AWWA dealing with Cryptosporidium. Other articles cover the Las Vegas outbreak, detection methods, assessing plant performance, and risk assessment. The areas of waterborne disease surveillance and basic concepts in epidemiology are also discussed.

This article describes the sequence of events leading to the recognition of the Milwaukee outbreak and the subsequent investigation by a team from the Water Supply and Water Resource Division of the US EPA. The specifications and operation of the supect water treatment plant are detailed, and the investigation into events leading up to the outbreak is discussed.

The outbreak was associated with a change in coagulant material from aluminium sulphate to polyaluminium chloride. It is suggested that lack of experience with use of the new coagulant at this plant led to difficulties in control of the flocculation process and consequent failure to effectively remove particulates from the source water. The turbidity of the source water from Lake Michigan was elevated during this time period, and investigations showed that other treatment plants also encountered problems in control of turbidity in finished water however no outbreaks were associated with these plants.

Reduction of risk of watery diarrhea with point-of-use water filters during a massive outbreak of waterborne Cryptosporidium infection in Milwaukee, Wisconsin, 1993.

Addiss DG, Pond RS, Remshak M, Juranek DD, Stokes S, Davis JP. Am-J-Trop-Med-Hyg. (1996) 54 p549-53.

The effectiveness of point-of-use home water filters in the prevention of diarrhoeal illness associated with Cryptosporidium was evaluated during the Milwaukee cryptosporidiosis outbreak. Residents with drinking water filters were recruited by a television advertising appeal on April 7 1993, the

same day that a boil water advisory was issued to residents. The water .treament plant suspected to be the source of the outbreak was also shut down on this date.

A self-administered questionnaire was completed by 99 filter owners in regard to their sources of drinking water, the characteristics of their home filters and diarrhoeal illness during the outbreak. The results of the questionnaire suggested that use of a submicron point-of-use home water filter substantially reduced the risk of diarrhoeal illness.

Among the 106 residents of households with submicron filters, 20% reported to have had diarrhea compared with 43% of the 246 residents of households with point-of-use filters pore size >1micron. Those who owned submicron filters and avoided drinking unfiltered tap water inside and outside the home had the greatest protection against diarrhoeal illness.

Outbreak of Cryptosporidiosis associated with a disinfected groundwater supply.

Bridgman SA, Robertson RM, Syed Q, Speed N, Andrews N, Hunter PR. Epidemiol-Infect. (1995) 115 p555-66.

In Warrington, North-West England, 47 cases of cryptosporidiosis were recorded between November 1992 and February 1993, most of these in the first month. A strong statistical association was found between cases and residence in an area supplied by two groundwater sources. A case-control study showed an association between drinking unboiled tap water from these sources, and a dose-response relationship was found. No oocysts were detected in the water supply.

It was found that during very heavy rainfall one water source drained water directly from a field containing livestock faeces and bypassed natural sandstone filtration. At the time of infection exceptionally heavy rain probably occurred. When the original water supply was withdrawn the outbreak subsided rapidly thus providing strong evidence that this outbreak was waterborne.

(Continued on p12)



Program 1 Personnel We continue our series of mini-CVs on people working in Program 1 of the CRCWQT.

Dr Margaret Hellard

Ms Andrea Hinwood

Dr Wayne Smith

Margaret Hellard holds a CRCWQT PhD Research Scholarship with the Department of Epidemiology and Preventive Medicine, Monash University. Prior to this appointment she gained her medical qualifications at Monash University and trained as an infectious diseases physician in Melbourne.

Margaret then worked for the Communicable Diseases Unit of the World Health Organisation in Geneva before returning to Melbourne. She has also worked as a part time Lecturer at DEPM and undertaken research on the assessment of microbiological risks associated with drinking water. Her current research interests are the Water Filter Study, community gastroenteritis and multiresistant organisms in a hospital setting.

Andrea Hinwood holds a Masters degree in Applied Science from RMIT, and worked with the Victorian EPA prior to taking up PhD studies at DEPM. Her research work centres on the human health impact of environmental arsenic contamination. In 1995 Andrea carried out a pilot study to trial recruitment, sampling and analysis methodologies to be utilised in a larger study of arsenic exposure and absorption. The main study is now underway, with the fieldwork phase and sample collection expected to be completed by late 1997.

During her PhD canditure Andrea chaired the Technical Options Committee on Aerosols, Sterilants, Miscellaneous uses and CTC for the United Nations Environment Programme on reduction of Ozone Depleting Substances, and was a member of the Technology and Economic Options Committee.

Wayne Smith received his medical degree from Newcastle University, and the degree of Master of Public Health from the University of Sydney. After clinical experience in a number of Sydney hospitals, Wayne worked in the NSW Health Department as a Public Health Officer in the Epidemiology Branch, and later as an NHMRC/PHRDC Research Fellow in the Department of Community Medicine at Westmead Hospital.

Wayne took up his present position as Fellow in Epidemiology at NCEPH in 1995, and has worked on a number of projects including asthma and air pollution, population survey methods, the Blue Mountain Eye Study, palliative care, and accident prevention in the elderly. Wayne is also Course convenor of the Graduate Diploma/Master in Population Health program.



Ms Elisa Bastone

Ms Pam Lightbody

Dr Alex Padiglione

Elisa Bastone was recently awarded her Masters degree in Applied Microbiology from RMIT. Her research studies in the Department of Clinical Pharmacology at the Alfred Hospital, included the development and use of dynamic in-vitro models and clinical trials to determine the efficacy and safety of high dose aminoglycoside antibiotic therapy.

In her present position as Research Fellow in DEPM she is primarily involved with the EnvAs study, which aims to determine the absorption and health impact of arsenic from environmental sources in rural Victoria. For the last few months Elisa has been busy recruiting participants for the study, and collecting biological and environmental samples for arsenic analysis.

Pam Lightbody completed a Science Degree at Monash University majoring in Environmental Science in 1990 and a Certificate in Office Practices in 1994. She has worked as a "Person Friday" for an accounting firm and as a Seminar Coordinator for a computer magazine since leaving university.

Pam began her work at DEPM as a part-time Research Assistant on the Healthwise Study (a major occupational health study for Alcoa Australia). In mid-1996 she began working fulltime on CRCWQT projects at DEPM. Pam maintains the literature collection and database for the water research group, provides research support for a number of projects and is Assistant Editor for the Health Stream Newsletter.

Alex Padiglione is an Infectious Diseases Physician, currently employed as a lecturer at the Department of Epidemiology and Preventive Medicine at Monash University. He graduated with Honours in Medicine at Monash University in 1986, and has spent most of the last decade working in clinical medicine at both the Alfred and Fairfield hospitals, during which time his research interests have included areas in HIV medicine and tropical diseases.

Alex’s current research interests include pneumococcal pneumonia, travel medicine and community gastroenteritis. As part of the CRC for Water Quality and Treatment he is working on the project “ The early detection of outbreaks of waterborne gastroenteritis - feasibility study”.



From the Literature (continued from p9)

It is recommended that guidelines for protection of groundwater are implemented with raw groundwater routinely monitored for microbiological contamination. Water catchment areas should be assessed in risk surveys.

A mixed outbreak of Cryptosporidium and Campylobacter infection associated with a private water supply.

Duke LA, Breathnach AS, Jenkins DR, Harkis BA, Codd AW. Epidemiol-Infect. (1996) 116 p303-8.

During an outbreak of gastroenteritis in which 43 people were affected, Cryptosporidium and Campylobacter were isolated from stool specimens and in two cases dual infection was found. The cases had all drunk unboiled water from a private water supply that was untreated. The source of contamination was presumed to be either three lamb carcases which were found in a collection chamber connected to the water supply or run-off slurry from surrounding fields. Maintenance and monitoring issues relating to private water supplies are discussed in this article and the problems associated with such supplies.

Outbreak of cryptosporidiosis at a day camp--Florida, July-August 1995.

Morbidity and Mortality Weekly Report. (1996) 45(21) p442-4.

This is a summary of an investigation into an outbreak of gastroenteritis which occurred in July 1995 at a day camp on the grounds of a public elementary school in Florida with both children and counsellors affected. Cryptosporidium parvum was isolated from the stools of several affected people.. No apparent contamination was found in the municipal water supply to the site. Faecal contamination of an outdoor water tap and hose used to fill water coolers was suspected as the mechanism of infection.

An outbreak of cryptosporidiosis associated with a resort swimming pool.

MacKenzie WR, Kazmierczak JJ, Davis JP. Epidemiol-Infect. (1995) 115 p545-53.

In late April 1993 an outbreak of cryptosporidiosis occurred among resort hotel guests, it was temporally associated with the Milwaukee outbreak but distant geographically. A case-control study was performed among a sample of groups who stayed at the resort hotel during the risk period and among groups whose members reported illness. 120 people were interviewed, 51 of these meeting the case definition.

Swimming in the resort pool and consuming ice cream from the hotel’s ice machines was significantly associated with case status. After restricting analysis to laboratory-confirmed cases and controls, swimming in the pool was the only significant risk factor associated with the illness. Swimming pools should therefore be considered as possible sources of transmission in localised outbreaks.

Cyanobacteria:

Detection of microcystins, a blue-green algal hepatotoxin, in drinking water sampled in Haimen and Fusui, endemic areas of primary liver cancer in China, by highly sensitive immunoassay.

Ueno Y, Nagata S, Tsutsumi T, Hasegawa A, Watanabe MF, Park HD, Chen GC, Chen G, Yu SZ. Carcinogenesis. (1996) 17 p1317-21.

An epidemiological survey conducted in Haimen and Fusui in China showed a close correlation between incidence of primary liver cancer (PLC) and the drinking of pond and ditch water. The aim was to determine whether contamination by microcystins (MC), hepatotoxic peptides produced by blue green algae, was occurring in the endemic areas of PLC in China. MC was monitored by a highly sensitive enzyme-linked immunosorbent assay.



A total of 1135 water samples were collected during 3 trials carried out in 1993-4 in Haimen city. The first trial in September 1993 found 3 out of the 14 ditch specimens were positive for MC. The second trial where samples were collected from ponds/ditches, rivers, shallow wells, and deep wells during all of 1994 revealed MC levels were highest during June to September. The third trial in July 1994 of 989 different water samples from a variety of water sources showed that 17% of pond/ditch water, 32% river water and 4% of shallow well water were positive for MC. MC was not detected in deep well water.

A survey on 26 drinking water samples in Fusui demonstrated a high contamination frequency of MC in the water of pond/ditches and rivers. These results support the hypothesis that MC in drinking water from ponds/ditches and/or rivers is one of the risk factors for high PLC in China. Based on these and previous findings an advisory level of MC in drinking water of 0.01 µg/l was proposed.

E. coli:

From the Centers for Disease Control and Prevention. Lake-associated outbreak of Escherichia coli 0157:H7--Illinois, 1995.

JAMA. (1996) 275 p1872-3.

On July 5, 1995 five cases of Escherichia coli 0157:H7 infection among children in Rockford, Illinois were reported to the Winnebago County Health Department. After interviewing the children’s parents it was revealed that they had all visited an Illinois state park with a lake swimming beach on June 24-25. The swimming beach was closed on July 6 because of suspected transmission of infection through lake water. Two water samples that had been collected at the beach on June 21 had levels of 660 and 900 E. coli per 100 ml. On July 10 the level of E. coli was >500 per 100ml in two out of six beach water samples. Faecal coliform levels were high on July 10 after no one had been swimming in the water for 4 days, this indicating that the water contamination was possibly by nonhuman sources.

Helicobacter pylori:

The transmission of Helicobacter pylori. A critical review of the evidence.

Goodman KJ, Correa P. Int-J-Epidemiol. (1995) 24 p875-87.

Infection by Helicobacter pylori is a risk factor for the development of gastritis, duodenal ulcers and stomach cancer. It is estimated that H. pylori infection may contribute to about 55% of the worldwide 550,000 new cases of stomach cancer each year. Knowledge of the mode(s) of transmission for this organism is limited. This paper reviews data regarding transmission pathways. Person to person transmission in early life is generally supported by reported observations of infection being linked to crowded residential conditions in childhood. Evidence for faecal-oral and oral-oral pathways has been yielded from laboratory studies. Waterborne or zoonotic transmission has not been ruled out either. There is the possibility of multiple transmission pathways as no single mode appears to predominate.

Helicobacter pylori infection in the Colombian Andes: a population-based study of transmission pathways.

Goodman KJ, Correa P, Tengana-Aux HJ, Ramirez H, DeLany JP, Guerrero-Pepinosa O, Lopez-Quinones M, Collazos-Parra T. Am-J-Epidemiol. (1996) 144 p290-9.

In 1992 a census sample of 684 2-9 year old children in a rural community in Colombian Andes was studied in regard to Helicobacter pylori infection and exposures relevant to person-to-person, waterborne, foodborne, and zoonotic transmission. H. pylori prevalence was 69%, prevalence increasing with age from 2 to 9 years. A higher percentage of males compared to females were infected from 3 years onwards.

The strongest predictor of H. pylori status was the number of persons who lived in the home, the number of children being of more importance than adults. The odds of infection were increased by



swimming in rivers, streams and pools or using streams as a drinking water source. Children who frequently consumed raw vegetables and had contact with sheep were likely to have increased prevalence odds also. The results support the possibility of multiple pathways of transmission.

Hepatitis:

A waterborne outbreak of hepatitis E virus transmission in southwestern Vietnam.

Corwin AL, Khiem HB, Clayson ET, Pham KS, Vo TT, Vu TY, Cao TT, Vaughn D, Merven J, Richie TL, Putri MP, He J, Graham R, Wignall FS, Hyams KC. Am-J-Trop-Med-Hyg. (1996) 54 p559-62.

In June and July 1994 an outbreak of hepatitis E virus (HEV) occurred along the Hau river bordering Cambodia in southwestern Vietnam. Information was collected from 50 patient cases, 50 matched healthy controls and 50 geographic controls who lived 50 km upriver. Cases showed a significantly higher (78%) prevalence of immunoglobulin G (IgG) to HEV than among geographic (38%) and control populations (38%).

Immunoglobulin M to HEV was detected in 16% of patients sera and HEV RNA was detected in 6% of sera. RNA was not detect in either of the control groups. Primarily adults were represented among clinical cases. Most of the cases and controls (96%) used river water for drinking and bathing. A negative association was found between boiling of drinking water and IgG anti-HEV seropositivity. A contributing factor to the outbreak may have been unusually heavy rainfall.

Legionnaires’ disease:

Risk factors for domestic acquisition of Legionnaires disease. Ohio Legionnaires Disease Group.

Straus WL, Plouffe JF, File TM Jr, Lipman HB, Hackman BH, Salstrom SJ, Benson RF, Breiman RF. Arch-Intern-Med. (1996) 156 p1685-92.

A case-control study was undertaken in 15 hospitals in 2 Ohio counties. 146 adults who had been diagnosed with community-acquired nonepidemic Legionnaires disease were each compared with 2 hospital-based control patients matched for age, sex and underlying illness category. An interview and home survey were conducted to estimate the risk of acquiring Legionnaires disease associated with different exposures.

Independent risk factors for Legionnaires disease were shown to be a nonmuniciple water supply, recent residential plumbing repairs and smoking. Other possible risk factors were electric (vs gas) water heaters, working more than 40hrs weekly and spending nights away from home before the illness.

Residential Legionella colonisation was associated with lower chlorine concentrations in potable water and lower water heater temperatures. From this study it can be concluded that a portion of sporadic cases of Legionnaires disease may be residentially acquired. Strategies to reduce this domestic risk may include consistent chlorination of potable water, increasing the temperature of water heaters and limiting the exposure to aerosols after domestic plumbing repairs.

Aluminium:

Can the controversy of the role of aluminium in Alzheimer's Disease be resolved? What are the suggested approaches to this controversy and methodological issues to be considered?

Savory J, Exley C, Forbes WF, et al. (1996) J-Toxicol-Envir-Health 48 p615-635.

This special issue of the Journal of Toxicology and Environmental Health contains several papers summarising the proceedings of a workshop on Aluminium Toxicity held in Vancouver in July 1995. The workshop specifically aimed at summarising current knowledge on unresolved issues and stimulating discussions on new directions and methodologies for research.



In this paper, the authors discuss the possible role of aluminium (Al) in Alzheimer's disease (AD). They begin by noting the abundance of aluminium in the environment - it is the third most abundant element after oxygen and silicon, and the most common metal on earth. The evidence for elevated levels of aluminium in the brains of people with AD is then discussed. Studies in the 1970s and 80s used bulk analysis of brain tissue to determine Al levels, more recent studies have used microprobe techniques in attempts to specifically measure the Al content of neurofibrillary tangles. It is concluded that the differences in experimental techniques in each laboratory and the small number of brains examined in each study preclude a decision on this issue.

The role of Al exposure in the workplace and in drinking water is reviewed, and it is noted that one reason for the research emphasis on drinking water is that data on the Al content of drinking water are readily available whereas data on other sources of exposure are much more fragmentary. Studies on workers in the aluminium industry have not yielded clear cut evidence of increased AD risk.

Epidemiological studies on drinking water have given inconsistent results, and have used variable criteria to define AD. The relatively recent discovery of genes which may predispose some individuals to AD has opened new avenues of research. A two year clinical trial of the chelating agent desferroxamine showed some benefit in reducing the rate of progression in AD patients, however this agent chelates other trivalent cations (such as iron) and the study design had some shortcomings (eg a single blind design comparing an injection of DFO with a tablet placebo).

Animal studies have been carried out mainly in rabbits as they exhibit much greater sensitivity to the neurotoxic effects of Al than rats and mice. However the biochemical and structural properties of the brain lesions induced in rabbits by Al treatment differ markedly from those found in humans, and the relevance of this model system has been questioned.

The authors conclude that although many questions remain unanswered, "there are strong indications that Al might be one of several factors resulting in Alzheimer's Disease and perhaps other neurodegenerative disorders".

Arsenic:

Geographical and temporal differences in the urinary excretion of inorganic arsenic: a Belgian population study.

Buchet JP, Staessen J, Roels H, Lauwerys R, Fagard R. Occup-Environ-Med.(1996) 53 p 320-7.

A study of the Belgian population to assess the geographical and temporal differences in exposure to inorganic arsenic was carried out. The CadmiBel study (1985-9) measured 24 hr urinary arsenic as an index of recent exposure in industrialised cities, a rural control area and in rural districts (Wezal, Lommel and Pelt) which had possibly been exposed through drinking water contaminated by emissions of nonferrous smelters. The 24 hr arsenic excretion was highest in Lommel and Pelt.

The PheeCad study (1991-5) re-examined the rural areas together with an urban control area. The result of this study was that mean 24 hr arsenic excretion was lower than six years earlier in the rural areas and similar to the excretion in the control town. Industry as well as drinking water was likely to be the source of increased exposure in the rural districts in 1985-9 because arsenic excretion did not follow regional arsenic drinking water content, stricter environmental regulations coincided with a drop in excretion over time and higher excretions were found the closer to the nearest smelter the individual resided. The high rural exposures in 1985-9 were not detected by arsenic monitoring networks.

Copper:

Copper in drinking water--an investigation into possible health effects.



Fewtrell L, Kay D, Jones F, Baker A, Mowat A. Public-Health. (1996) 110 p 175-7.

A study of the possible relationship between levels of copper in drinking water and the incidence of specified liver complaints presenting at a major UK paediatric liver unit was undertaken. Copper levels in public drinking water supplies were in general well below the EC standard of 3,000 micrograms/l. A slightly greater number of samples from private supplies were found to exceed this standard. Data was examined of infants with specified liver complaints reporting to Kings College Hospital, London. All the patients, where addresses could be determined, were found to live in areas served by public drinking water supplies and therefore not likely to have been exposed to elevated copper concentrations.

Detection methods:

Detection of a single viable Cryptosporidium parvum oocyst in environmental water concentrates by reverse-transcription-PCR.

Stinear T, Matusan A, Hines K, and Sandery M. Appl-Environ-Microbiol (1996) 62 p3385-3390.

This paper describes an extremely sensitive method for the assay of viable Cryptosporidium parvum oocysts, based on detection of mRNA (messenger RNA) coding for the heat shock protein hsp70. The results suggest that this technique can provide a sensitive and specific assay for viable C. parvum oocysts, although this is yet to be confirmed in field situations.

Method 4 x environmental water samples (20 litres each from a river, a reservoir, a bore and a tap) were collected and processed as per current oocyst concentration methods using calcium carbonate flocculation and Percoll sucrose density gradient centrifugation, with final resuspension of each sample in 10ml of phosphate buffered saline. 1ml volumes of these "concentrates" (representing debris and contaminants normally expected in water samples) were then seeded with various dilutions of C. parvum oocysts prepared from infected calf faecal

extracts. Oocyst concentrations were determined by immunofluorescent staining with a commercial kit, while viability was assessed using DAPI-PI staining. Non-seeded concentrates were also included as blank controls to verify the absence of oocysts in the original water samples.

The seeded mixtures were centrifuged and resuspended then heated to 45°C for 20 min to induce production of mRNA coding for heat shock protein hsp70. Oocysts were ruptured by 5 freeze thaw cycles (liquid N2 / 65°C), and immediately processed to extract mRNA. Efficient recovery of mRNA was achieved by the use of magnetic beads coated with oligo(dT)25 which hybridises to the poly(dA) sequences characteristic of mRNA.

A reverse transcription (RT) reaction was then carried out to generate a DNA product from any hsp70 mRNA which was present, followed by a polymerase chain reaction to amplify the amount of DNA product. Aliqouts of the final reaction mixture were then electrophoresed on polyacrylamide and agarose gels, and the PCR products were visualised directly by staining with silver nitrate (polyacrylamide gels) or by staining with ethidium bromide and UV transillumination (agarose gels). Where the amount of DNA product was insufficient for direct visualisation, the DNA was transferred to nylon membranes and detected by Southern hybridisation with digoxigenin-alkaline phosphatase staining.

Results The technique was successful in detecting oocyst concentrations as low as 1 viable oocyst per inoculum in all 4 water types. For reticulated and bore water concentrates the PCR product could be easily visualised on polyacrylamide gels, while for samples of river and reservoir water, Southern hybridisation was required.

The specificity of the method was tested by screening for generation of a PCR product from DNA extracts from a variety of organisms which might be found in environmental water samples (including other protozoa, bacteria and helminths). Some of the tested organisms produced faint bands on gels but none produced a PCR product of similar size to the C. parvum product. One puzzling aspect of the results is



that the heat shock step did not appear to be necessary for detection of the hsp70 PCR product. The authors suggest that synthesis of hsp70 mRNA may have been induced by other factors in oocyst preparation prior to this step.

Evaluation of a commercial enzyme immunoassay (EIA) and immunofluorescent antibody (IFA) test kits for the detection of Cryptosporidium oocysts of species other than Cryptosporidium parvum.

Graczyk, TK, Cranfield MR and Fayer R (1996) Am J Trop-Med-Hyg 54 p274-279.

Three commercially available kits ( 1 x EAI, 1 x direct IFA, 1 x indirect IFA) were tested against a total of 30 Cryptosporidium isolates and 14 other faecal pathogens. All 3 kits gave "false positive" results against some non-Cryptosporidium parvum isolates of Cryptosporidium, but did not react with the other pathogens. The EIA kit (designed for faecal testing) reacted with 6 of 25 non-C.parvum isolates, while both the direct IFA (designed for faecal testing) and the indirect IFA (designed for environmental samples) reacted with 19 of the 25 non-C.parvum samples.

The samples showing a false positive reactions with the EIA kit were 1 from a Guinea pig (C. wrairi), 2 from camels (C. muris-like), 2 from domestic turkeys (C. meleagridis) and 1 from a lizard (unclassified). These 6 isolates also gave false positive reactions with direct and indirect IFA kits, as did 9 isolates from snakes (C. serpentis), 1 from a cow (C. muris), 1 from a rock hyrax (C. muris), 1 from a turtle (unclassified), and 1 additional isolate from a lizard (unclassified). None of the kits reacted with the single tested isolate of C. baileyi from a domestic chicken.

Using a computer model to simulate repeated sampling of an environment with mixed Cryptosporidium population, the authors estimated that up to 35% of environmental samples may be wrongly classified as containing C. parvum by the IFA kits or up to 12% wrongly classified by the EIA kit.

The molecular epidemiology of Giardia Lamblia: a sequence-based approach.

Baruch AC, Isaac-Renton J and Adam, RD (1996) J Infect-Dis 174 p233-236 .

This paper describes the use of a PCR technique to detect differences in the DNA sequence of the triose phosphate isomerase (tim) gene in different isolates of Giardia lamblia. This protozoan parasite is known to infect a variety of mammalian hosts including man, but there is disagreement in the literature over whether infection can be readily transmitted to humans from non-human hosts. Three major sub groups have been defined by a number of classification methods, and each contains both human and animal isolates. The DNA sequence of the tim gene was determined for 13 G. lamblia isolates and compared to the sequence of the same gene from the prototype strain of each sub group. By examining the differences in gene sequence between the isolates, a number of sites were identified which could be used to distinguish the 3 groups. These were DNA sequences where nucleotide changes resulted in loss of a restriction enzyme cut site compared to members of other groups.

It was estimated that the PCR technique would allow the detection and classification of as few as 5-10 oocysts using a commercially available DNA extraction kit, without the need to grow isolates in vitro. The authors conclude that this technique will be useful for rapid investigation of outbreaks and may help to resolve the question of zoonotic transmission.

A simple device for the concentration and detection of enterovirus, hepatitis E virus and rotavirus from water samples by reverse transcription-polymerase chain reaction.

Jothikumar N, Khanna P, Paulmurugan R, Kamatchiammal S, Padmanabhan P. J-Virol-Methods. (1995) 55 p401-15.

Simultaneous concentration of enteroviruses, hepatitis E virus, and rotavirus from drinking water samples was achieved through a filtration column



containing granular activated carbon (GAC). For effective desorption and elution of viruses from GAC, urea-arginine phosphate buffer at pH 9.0 was used. Magnesium chloride was used to further concentrate the viruses which enabled nucleic acid extraction, cDNA synthesis, amplification with a specific set of primers for enterovirus, hepatitis E virus and rotavirus. The polymerase chain reaction products were then confirmed by Southern transfer and hybridisation with relevant probes. The efficacy of the protocol was established. The protocol was used for the detection of waterborne viruses from 24 drinking water sources in urban areas of New Delhi.

Risk Assessment

Cancer: science and society and the communication of risk.

Calman KC. British Medical J (1996) 313 p799-802.

This article is based on a lecture given by Kenneth Calman, Chief Medical Officer of the UK Department of Health, in September of this year. The concepts expounded here were repeated in Dr Calman’s Annual Report and discussed in the News section of the journal Nature on 3rd October.

The article discusses the role and limitations of epidemiological data in setting public health policies, the importance of perception, choice and behaviour in assessment of risk, and methods of communicating information about health risks to the public.

The author advocates the adoption of standardised nomenclature to describe and quantify risks. He proposes that the word “safe” should be seen to mean “negligible risk” (ie less than 1 in a million probabilty of an adverse event occurring) rather than “no risk”. Other gradations proposed are “minimal”, (between 1 in a million and 1 in 100,000), “very low” (1 in 100,000 to 1 in 10,000), “low” (1 in 10,000 to 1 in 1,000), “moderate” (1in 1,000 to 1 in 100) and “high” (greater than 1 in 100). This idea is illustrated by a table of risks showing the risk of death or adverse event occurring to an individual in a 1 year interval.

The paper also discusses the need for public education about risk assessment, and increased understanding that scientific knowledge cannot

provide definitive answers to many important public health questions. It is suggested that the issues raised in relation to cancer prevention, screening and treatment provide a relevant model for other health issues.

List of Articles Water Quality: Analysis of virulence characteristics of bacteria isolated from bottled, water cooler and tap water. Edberg SC, Gallo P, Kontnick C. Microbial Ecology in Health and Disease (1996) 9 p67-77. Drinking water sources, mortality and diarrhoea morbidity among young children in northern Ghana. Shier RP, Dollimore N, Ross DA, Binka FN, Quigley M, Smith PG. Trop-Med-Int-Health. (1996) 1 p334-41. Water, waste, and well-being: a multicountry study. Esrey SA. Am-J-Epidemiol. (1996) 143 p608-23. Impact of liquid waste disposal on potable groundwater resources near Perth, Western Australia. Appleyard SJ. Environmental Geology. (1996) 28 p106-110. Hand washing with soap reduces diarrhoea and spread of bacterial pathogens in a Bangladesh village. Shahid NS. Greenough WB. Samadi AR. Huq MI. Rahman N. Journal of Diarrhoeal Diseases Research. (1996) 14 p85-89. Laboratory experiments to investigate human sensitivity to changes in water clarity. Smith DG. Perrone JA. Journal of Environmental Management. (1996) 48 p139-154. Cryptosporidium: Milwaukee’s crypto outbreak: investigation and recommendations. Fox KR and Lytle DA. J-AWWA (1996) 88 (9) p87-94. Reduction of risk of watery diarrhea with point-of-use water filters during a massive outbreak of waterborne Cryptosporidium infection in Milwaukee, Wisconsin, 1993. Addiss DG, Pond RS, Remshak M, Juranek DD, Stokes S, Davis JP. Am-J-Trop-Med-Hyg. (1996) 54 p549-53. Outbreak of cryptosporidiosis associated with a disinfected groundwater supply. Bridgman SA, Robertson RM, Syed Q, Speed N, Andrews N, Hunter PR. Epidemiol-Infect. (1995) 115 p555-66.



A mixed outbreak of Cryptosporidium and Campylobacter infection associated with a private water supply. Duke LA, Breathnach AS, Jenkins DR, Harkis BA, Codd AW. Epidemiol-Infect. (1996) 116 p303-8. Outbreak of cryptosporidiosis at a day camp--Florida, July-August 1995. MMWR. (1996) 45 p 442-4. An outbreak of cyptosporidiosis associated with a resort swimming pool. MacKenzie WR, Kazmierczak JJ, Davis JP. Epidemiol-Infect. (1995) 115 p545-53. Cyanobacteria: Detection of microcystins, a blue-green algal hepatotoxin, in drinking water sampled in Haimen and fusui, endemic areas of primary liver cancer in China, by highly sensitive immunoassay. Ueno Y, Nagata S, Tsutsumi T, Hasegawa A, Watanabe MF, Park HD, Chen GC, Chen G, Chen G, Yu SZ. Carcinogenesis. (1996) 17 p1317-21. Automated purification of microcystins. Edwards C, Lawton LA, Coyle SM, Ross P. Journal of Chromatography (1996) 734 p175-182. Toxic and non-toxic strains of the cyanobacterium Microcystis aeruginosa contain sequences homologous to peptide synthetase genes. Meissner K, Dittmann E, Borner T. FEMS Microbiology Letters (1996) 135 p295-303. Biodegradation of microcystin-lr by indigenous mixed bacterial populations. Cousins IT,Bealing DJ, James HA, Sutton A. Water Research (1996) 30 p481-485. Algal bloom probability in a large subtropical lake. James RT. Havens KE. Water Resources Bulletin. (1996) 32 p995-1006. Disinfection byproducts Contributions of disinfection by-products to activity inducing chromosomal aberrations of drinking water. Itoh S. Matsuoka Y. Water Research. (1996) 30 p1403-1410. E. coli: From the Centers for Disease Control and Prevention. Lake-associated outbreak of Escherichia coli 0157:H7--Illinois, 1995. JAMA. (1996) 275 p1872-3.

Helicobacter pylori: The transmission of Helicobacter pylori. A critical review of the evidence. Goodman KJ, Correa P. Int-J-Epidemiol. (1995) 24 p875-87. Helicobacter pylori infection in the Colombian Andes: a population-based study of transmission pathways. Goodman KJ, Correa P, Tengana-Aux HJ, Ramirez H, DeLany JP, Guerrero-Pepinosa O, Lopez-Quinones M, Collazos-Parra T. Am-J-Epidemiol. (1996) 144 p290-9. Hepatitis: A waterborne outbreak of hepatitis E virus transmisssion in southwestern Vietnam. Corwin AL, Khiem HB, Clayson ET, Pham KS, Vo TT, Vu TY, Cao TT, Vaughn D, Merven J, Richie TL, Putri MP, He J, Graham R, Wignall FS, Hyams KC. Am-J-Trop-Med-Hyg. (1996) 54 p559-62. Legionnaires’ disease: Risk factors for domestic acquisition of legionnaires disease. Ohio Legionnaires Disease Group. Straus WL, Plouffe JF, File TM Jr, Lipman HB, Hackman BH, Salstrom SJ, Benson RF, Breiman RF. Arch-Intern-Med. (1996) 156 p1685-92. Outbreak of Legionnaires’ disease among cruise ship passengers exposed to contaminated whirlpool spa. Jernigan DB, Hofmann J, Cetron MS, Genese CA, Nuorti JP, Fields BS, Benson RF, Carter RJ, Edelstein PH, Guerrero IC, Paul SM, Lipman HB, Breiman R. Lancet. (1996) 347 p494-9. Aluminium: Can the controversy of the role of aluminium in Alzheimer's Disease be resolved? What are the suggested approaches to this controversy and methodological issues to be considered? Savory J, Exley C, Forbes WF, et al. (1996) J-Toxicol-Envir-Health 48 p615-635. Determination of selected trace elements in patients affected by dementia. Molaschi M. Ponzetto M. Bertagna B. Berrino E. Ferrario E. Archives of Gerontology & Geriatrics. (1996) S5 p39-42 . Aluminium and biological systems - an introduction [review]. Williams RJ. Coordination Chemistry Reviews.(1996) 149 p1-9. A case-control study of Alzheimers disease and aluminium occupation. Salib E. Hillier V. British Journal of Psychiatry. (1996)168 p244-249.



Aluminium and Alzheimers disease - review of possible pathogenic mechanisms [review]. Armstrong RA. Winsper SJ. Blair JA. Dementia.(1996) 7 p1-9. Arsenic: Geographical and temporal differences in the urinary excretion of inorganic arsenic: a Belgian population study. Buchet JP, Staessen J, Roels H, Lauwerys R, Fagard R. Occup-Environ-Med. (1996) 53 p 320-7. Copper: Copper in drinking water--an investigation into possible health effects. Fewtrell L, Kay D, Jones F, Baker A, Mowat A. Public-Health. (1996) 110 p 175-7. Detection methods: Detection of a single viable Cryptosporidium parvum oocyst in environmental water concentrates by reverse-transcription-PCR. Stinear T, Matusan A, Hines K, and Sandery M. Appl-Environ-Microbiol (1996) 62 p3385-3390. Evaluation of a commercial enzyme immunoassay (EIA) and immunofluorescent antibody (IFA) test kits for the detection of Cryptosporidium oocysts of species other than Cryptosporidium parvum. Graczyk, TK, Cranfield MR and Fayer R (1996) Am J Trop-Med-Hyg 54 p274-279. The molecular epidemiology of Giardia Lamblia: a sequence-based approach. Baruch AC, Isaac-Renton J and Adam, RD (1996) J Infect-Dis 174 p233-236. A simple device for the concentration and detection of enterovirus, hepatitis E virus and rotavirus from water samples by reverse transcription-polymerase chain reaction. Jothikumar N, Khanna P, Paulmurugan R, Kamatchiammal S, Padmanabhan P. J-Virol-Methods. (1995) 55 p401-15.

Disclaimer

Whilst every effort is made to reliably report the data and comments from

the journal articles reviewed, no responsibility is taken for the accuracy

of articles appearing in Health Stream, and readers are advised to refer

to the original papers for full details of the research.

Risk Assessment Cancer: science and society and the communication of risk. Calman KC. British Medical J (1996) 313 p799-802. Miscellaneous: Radium in drinking water and risk of bone cancer in Ontario youths: a second study and combined analysis. Finkelstein MM, Kreiger N. Occup-Environ-Med. (1996) 53 p305-11.

Forthcoming Meetings Management Committee Meeting The next meeting of the Management Committee of the CRCWQT will take place on Wednesday 29th January 1997 in Adelaide. Venue to be confirmed. Board of Management The next meeting of the Board of Management of the CRCWQT will take place on 3rd March 1997 in Sydney. The meeting will be held at the Prospect Water Filtration Plant, and will be hosted by AWS.


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