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The reuse of domestic greywater has become common in Australia, especially during periods of extreme drought. Greywater is typically used in a raw, untreated form, primarily for landscape irrigation, but more than a quarter of greywater users irrigate vegetable gardens with the water, despite government advice against this practice. Greywater can be contaminated with enteric pathogens and may therefore pose a health risk if irrigated produce is consumed raw. A quantitative microbial risk assessment (QMRA) model was constructed to estimate the norovirus disease burden associated with consumption of greywater-irrigated lettuce. The annual disease burdens (95th percentile; DALYs per person) attributed to greywater irrigation ranged from 2 × 10(-8) to 5 × 10(-4), depending on the source of greywater and the existence of produce washing within households. Accounting for the prevalence of produce-washing behaviours across Melbourne, the model predicted annual disease burdens ranging from 4 × 10(-9) for bathroom water use only to 3 × 10(-6) for laundry water use only, and accounting for the proportionate use of each greywater type, the annual disease burden was 2 × 10(-6). We recommend the preferential use of bathroom water over laundry water where possible as this would reduce the annual burden of disease to align with the current Australian recycled water guidelines, which recommend a threshold of 10(-6) DALYs per person. It is also important to consider other exposure pathways, particularly considering the high secondary attack rate of norovirus, as it is highly likely that the estimated norovirus disease burden associated with greywater irrigation of vegetables is negligible relative to household contact with an infected individual., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The volume of cold tap water consumed is an essential element in quantitative microbial risk assessment. This paper presents a review of tap water consumption studies. Study designs were evaluated and statistical distributions were fitted to water consumption data from The Netherlands, Great Britain, Germany and Australia. We conclude that the diary is to be preferred for collecting water consumption data. If a diary is not feasible, a 24 h recall would be the best alternative, preferably repeated at least once. From the studies evaluated, the mean daily consumption varies from 0.10 L to 1.55 L. No conclusions could be drawn regarding the effects of season, age and gender on tap water consumption. Physical activity, yearly income and perceived health status were reported to influence water consumption. Comparison of the different statistical probability distribution functions of the datasets demonstrated that the Poisson distribution performed better than the lognormal distribution as suggested by Roseberry and Burmaster. For quantitative microbiological risk assessment (QMRA) it is recommended to use country-specific consumption data and statistical distributions, if available. If no country specific data are available we recommend to use the Australian distribution data from the Melbourne diary study (Poisson, lambda=3.49 glasses/d) as a conservative estimate.

Background and Aim: Many individuals with gastrointestinal symptoms do not seek medical attention and so there is little known about the pathogens involved in most cases of community gastroenteritis. We aimed to identify the pathogens responsible for community gastroenteritis and to examine the associated symptoms., Methods: In a prospective study of 2811 subjects over 15 months, fecal pathogens were examined following highly credible gastroenteritis (HCG) events. The population consisted of family units of at least two children (< or =15 years-old) and two adults each. Fecal samples were tested for a range of bacterial, viral and protozoal pathogens. Gastroenteric episode duration and symptoms such as vomiting, nausea and diarrhea were measured., Results: One or more pathogens were identified in 198 of a total 791 specimens collected. Pathogens detected most often were Norovirus virus (10.7%), pathogenic E. coli (6.7%), Campylobacter spp. (3.0%) and Giardia sp. (2.5%). Children were more prone than adults to all the pathogens tested, except E. coli. Children infected with Campylobacter were 8.3 times more likely (95% CI: 2.7-25.4) to have a longer duration of diarrhea than children with Norovirus (P < 0.001). Similarly, children infected with E. coli had increased persistence of diarrhea compared to Norovirus (OR = 3.5; 95% CI: 1.3-9.5; P = 0.02). Infection with Norovirus in children meant greater persistence of vomiting symptoms than infection with Campylobacter (P = 0.005), E. coli (P = 0.03), or if no pathogen was identified (P = 0.004). Adults usually vomited for fewer days than children while duration of diarrhea was similar to children., Conclusions: Many of the pathogens responsible for cases of gastroenteritis in the Australian community are likely to go undetected by current surveillance systems and routine clinical practice.

Noroviruses are a major cause of both sporadic and epidemic gastroenteritis in humans, but the mechanisms by which norovirus circulates within the community are poorly understood. In this study, we examined the hypothesis that asymptomatic people act as a reservoir for norovirus. Faecal specimens from 399 asymptomatic individuals were tested for norovirus by reverse transcription polymerase chain reaction (RT-PCR) methodology, and no norovirus was detected. The failure to detect norovirus was not apparently due to the test sample being resistant to norovirus infection, nor to the presence of PCR inhibitors in the test sample. The findings suggest that, if norovirus is carried by asymptomatic people, the carriage rate is very low; the upper bound (95% confidence interval, binomial distribution) of the carriage rate was only 0.8%. Thus, it is unlikely that asymptomatic people are an important reservoir for norovirus.

Poor food handling practices in the home are a likely cause of gastroenteritis. This study examined how often reported practices in Australian homes met public health food safety recommendations. During 1998 in Melbourne, Australia, food handling and food storage questionnaires were completed by an adult member in 524 and 515 families, respectively. Each family consisted of at least two adults and two children. Respondents were surveyed regarding washing of hands, cutting boards, and fresh produce; use of kitchen cloths; egg storage; where cooked foods were cooled; the duration before refrigeration of cooked foods; where food types were positioned in the refrigerator; and the method of thawing chicken. Nearly every household reported handling food in a way that could cause food to become contaminated. Overall, 99.0% of respondents reported some form of mishandling, which encompassed 70.3% who handled food preparation surfaces poorly, 46.6% who did not wash their hands appropriately or in a timely manner, 41.7% who mishandled raw foods, and 70.1% who mishandled cooked foods. Food was inappropriately located in the refrigerator by 81.2%, and chicken was thawed using unsafe means by 76.3% of respondents. People preparing food in the home need to be reminded of the increased risk of disease that can arise from poor food handling practices.

Endemic gastroenteritis associated with the Norwalk-like viruses (NLVs) is little understood. This study tested for NLV in gastroenteritis cases in 257 households in Melbourne, Australia, for the period September 1997 to February 1999 by a reverse transcription hemi-nested polymerase chain reaction. Positive samples were studied by nucleotide sequencing and phylogenetic analysis. NLV was detected in 73 (11.4%) of 638 faecal specimens tested. Twelve (1.9%) were NLV genogroup 1 (G1) and 61 (9.6%) NLV genogroup 2 (G2). Gastroenteritis symptoms associated with NLV G2/no other pathogens were significantly more severe than where no NLV was detected. NLV G1 and NLV G2 were detected in adults and children, males and females. NLV G2 incidence showed a marked seasonal periodicity with significant peaks in the Australian late spring/early summer periods. NLV G1 seasonality was significantly different from that of NLV G2. Seven major NLV clusters were identified by phylogenetic analysis., (Copyright 2003 Wiley-Liss, Inc.)

Background and Aim: Gastroenteritis is a common illness that causes considerable morbidity in developed countries. Endemic gastroenteritis that is not associated with outbreaks causes the greatest number of cases, but information is limited about the burden of this disease, and the resources required to manage its impact on society. In the present study, we estimated the rate of endemic gastroenteritis, the number of visits to the local doctor, use of medication, and the cost of gastroenteritis in Australia., Methods: Data from a community-based study of gastroenteritis, a general practice surveillance network, the Australian Bureau of Statistics and the Health Insurance Commission were used to measure endemic gastroenteritis and other study outcomes. The results were then extrapolated to the Australian Community., Results: There were an estimated 0.8 cases of gastroenteritis per person per year in Australia. This equated to 15,173,430 cases of gastroenteritis in Australia annually. The age-standardized estimate of the total number of visits to the general practitioner (GP) for gastroenteritis was 1024,214 at a cost of 26,722,691 Australian dollars. The average cost of prescribed medication per visit was 6.83 Australia dollars; the estimated total cost of prescribed medication was 6995,381 Australian dollars. The estimated cost of over-the-counter medication was 14,587,477 Australia dollars. It was estimated that people working full or part-time had 0.13 days-off per person per year because of gastroenteritis, at a cost of 137,924,170 Australian dollars. The estimated total cost of endemic gastroenteritis in Australia was 342,855,616 Australian dollars of which 75,908,274 Australian dollars was direct medical costs and 266,947,342 Australian dollars was time costs and the costs for time off work to care for a sick family member., Conclusions: Endemic gastroenteritis is an important illness in both developed and developing countries. Although in developed countries, the majority of individual cases are mild to moderate in their severity; the overall costs are significant. The results highlight the need for ongoing research to identify the main causes of endemic gastroenteritis.

Objective: To provide recent data regarding the epidemiology of community-based respiratory infections in Australia., Methods: A longitudinal study between 1997-99 involving collection of a health diary from 600 families in Melbourne., Results: More than 80% of study participants reported at least one respiratory episode over 15 months. An average of 2.2 respiratory episodes per person per year was reported, with a mean episode duration of 6.3 days. On average, subjects were symptomatic for 4.2% of the study days. Compared with other age groups, children aged less than two years were most likely to have at least one respiratory episode, a greater number of episodes per person and the longest episode duration (6.8 days). Approximately, one in three (28.7%) respiratory episodes were associated with a doctor's visit, and one in four (23%) necessitated time off school or work. Exposure to other people with respiratory symptoms was commonly reported., Conclusions: Respiratory infections are common, cause a significant amount of morbidity, and are major contributors to the total community health burden., Implications: The direct and indirect costs of respiratory infections to the community are substantial.

The risk of contamination of drinking water supplies with microbial pathogens is minimised by modern approaches to water management, but continues to be the major public health concern. Chemical contaminants usually pose little health risk except at very high levels, but debate continues over the potential adverse health effects of low-level, chronic exposure to compounds such as disinfection byproducts. Recreational water contact can be associated with adverse health outcomes either from microbial infections or exposure to cyanobacterial toxins. Environmental issues such as increasing salinity and global warming are likely to affect the sustainability of our current drinking water supplies and increase the threat of waterborne disease outbreaks. New technologies, use of alternative water sources, such as rainwater tanks, water reuse and restrictions will undoubtedly be part of the solution to our diminishing water resources, but have the potential to introduce new health threats.

There are few data available on the incidence of endemic waterborne disease in the developed world. This study aims to determine if there was a measurable decline in gastroenteritis related faecal specimens following the introduction of water treatment. The rate of faecal specimens for gastroenteritis was obtained for 17 communities one year before and after the introduction of water treatment in two states of Australia between 1992 and 1996. Of these 17 systems, 10 had filtration added to existing disinfection, while seven had both disinfection and filtration or disinfection alone added to no existing treatment. The rate of faecal sampling varied from a reduction of 55% to an increase of 198%. Large changes in water quality parameters occurred following treatment but there was no significant correlation between these changes and changes in the rate of faecal specimens. In this study there was no consistent change in gastrointestinal related faecal specimens despite marked changes in water quality. This suggests that the reduction in endemic gastrointestinal disease as a result of the introduction of water treatment was small as a percentage of all gastroenteritis. However, water treatment remains essential to protecting public health.

Objectives: To describe the strategies adopted to maintain high level participation throughout a community based clinical trial, and the reasons given by participants for why they participated in the study., Design: Observational study., Setting: Community based clinical trial in Melbourne, Australia that ran for 68 weeks and involved 2811 community based individuals from 600 families. A high level of commitment was required of the families; each participant completed a Health Diary each week of the 68 week study, as well as answering numerous other questionnaires, and providing faecal and blood samples., Main Results: Only 41 of the 600 families withdrew from the study; the majority of these families withdrew because they sold their home and moved from the study area. The completion rate of Health Diaries averaged 90.7% over the 68 weeks of data collection. Of the 559 families who completed the study, 524 (93.7%) completed the Participation Questionnaire. The statement that received the highest rating for why families enrolled in the study was they thought the study was researching an important community issue. The statements that received the highest ratings for why families continued to participate in the study was the family being kept well informed about the study's progress and that the study was well run., Conclusions: The low numbers of withdrawals and the high level of participation throughout the study suggests the strategies of (a) having a non-aggressive recruitment method, (b) maintaining regular contact with the participants and (c) ensuring participants were kept well informed of the study's progress and constantly encouraged to continue participation were successful. The results also suggest people involve themselves in research because they perceive it to be of value to the community, not simply for personal gain. They indicated that they maintained their participation because it was a well run study and they were kept well informed throughout the study.

To assess the rate of fecal vancomycin-resistant enterococci (VRE) colon ization in Austalia, we examined specimens from 1,085 healthy volunteers. VRE was cultured from 2(0.2%) of 1,085 specimens; both were vanB Enter ococcus faecium, identical by pulsed-field gel electrophoresis, but with a pattern rare in Melbourne hospitals.

Strains of Pseudomonas aeruginosa resistant to gentamicin, tobramycin, streptomycin, and sulphonamide have been isolated from patients at two Sydney hospitals. The multiple resistance of all these strains was due to a transmissible plasmid. The significance of the identification of this plasmid, in this variety of strains and at two hospitals, for the treatment of Ps. aeruginosa infections is discussed.