First documented gymnasium cluster of COVID-19 with whole genome sequencing in Australia

Background

Transmission of coronavirus disease 2019 (COVID-19) has been demonstrated in fitness settings internationally. We report the first documented case of transmission of COVID-19 in a gymnasium in Australia in 2020.

Methods

Case finding and case interviews were conducted among attendees in a Western Sydney gymnasium, Australia. Whole genome sequencing using an amplicon-based approach was performed on all SARS CoV-2 polymerase chain reaction positive samples detected through surveillance.

Results

We show that five cases of COVID-19 were linked to the gymnasium, with transmission occurring on 7 July 2020, when the index case transmitted the infection to four other gymnasium attendees through the sharing of an enclosed space.

Conclusions

There is an ongoing risk of transmission of COVID-19 within gymnasium environments and they are justifiably classified as a 'high-risk' venue. There may be a need to expand ventilation and space requirements to prevent transmission of COVID-19 in such settings in the context of severe COVID-19 variants or to prevent respiratory disease transmission in general.

FluTracking: Weekly online community-based surveillance of influenza-like illness in Australia, 2019 Annual Report

Abstract

FluTracking provided evidence for an early, long, but moderate influenza season in the Australian community compared to prior years. Influenza-like illness (ILI) activity in 2019 peaked earlier (week ending 16 June) than any season on record in FluTracking data. ILI attack rates were above average early in the 2019 season (peak of 2.2%), and the duration of peak activity was longer than most prior years. However, ILI attack rates were lower than the five-year average in the latter half of the season. FluTracking participants reported higher vaccination coverage in 2019 (73.3%) compared with 2018 (65.7%), with the most notable increase in children aged less than five years (69.3% in 2019, compared to 55.6% in 2018). The total 2019 count of laboratory notifications (312,945) was higher than prior years (2007 onwards), and the peak weekly count of 18,429 notifications in 2019 was also higher than all prior years, except 2017. FluTracking makes a comparison to another surveillance system each year. The peak weekly percentage of calls to HealthDirect that were influenza-related was higher in 2019 (12.8%) than for 2014-2018 (range of 8.2-11.4% for peak week of activity each year). FluTracking participants reported a 2.5 times increase in influenza testing from 2018 to 2019 and a 1.5 times increase from 2017. Although 2019 was of higher activity and severity than 2018, Flutracking data indicates that 2019 was a lower activity and severity season than 2017, and notifications and influenza-related calls were heightened by increased community concern and testing.

FluTracking: Weekly online community based surveillance of influenza-like illness in Australia, 2018 Annual Report

FluTracking experienced major growth in 2018, with participation numbers increasing 34.1% from 2017. The addition of 16,881 new participants brought the total number of participants for 2018 to 45,532. A majority of participants continued to complete their survey within 24 hours of the email being sent (mean 74.3% responses received in 24 hours). The rate of influenza-like illness (ILI) in 2018 was the lowest since FluTracking commenced in 2007 and was consistently low across all ages. The peak weekly ILI rate was consistent with previous years, occurring during the week ending 19 August. This preceded the peak in laboratory-confirmed influenza notifications by three weeks. During the peak week of FluTracking, 2.1% of unvaccinated, and 1.9% of vaccinated participants reported fever and cough. By the final survey of 2018, 65.6% of participants had received the annual influenza vaccine, compared with 60.2% in 2017. Vaccination rates in participants under five years of age doubled from 23.7% in 2017, to 55.6% in 2018. During the peak four weeks of reported ILI, a lower percentage of participants sought medical care in 2018 compared to 2017 (36.7% and 42.3% respectively), and fewer participants reported a positive laboratory test for influenza (0.8% and 4.8%). Overall the severity of the 2018 season was one of the lowest FluTracking has recorded. Rates of both influenza laboratory notifications and general practitioner (GP) ILI consultations were lower in 2018 than most prior years. We found a reduction in the percentage of FluTracking participants with ILI who were tested for influenza (3.2% compared with 5.0% in 2017), and who visited a medical practitioner (36.7% compared with 42.3% in 2017). The drop in laboratory-confirmed cases and Australian Sentinel Practices Research Network (ASPREN) reported GP consultations concurs with our survey results that 2018 was a milder influenza season than many previous.

Influenza outbreaks in aged care facilities in New South Wales in 2017: impact and lessons for surveillance

Introduction

A record number of influenza outbreaks in aged care facilities (ACFs) in New South Wales (NSW) during 2017 provided an opportunity to measure the health impact of those outbreaks and assess the quality of routinely available surveillance data.

Methods

Data for all ACF influenza outbreaks in NSW in 2017 were extracted from the Notifiable Conditions Information Management System. The numbers of outbreaks, residents with influenza-like illness (ILI), hospital admissions and deaths were assessed. For each outbreak the attack rate; duration; timeliness of notification; resident and staff influenza vaccination coverage; and antiviral use for treatment or prophylaxis were analysed. Data were considered for NSW in total and separately for seven of the state's local health districts. Data completeness was assessed for all available variables.

Results

A total of 538 ACF outbreaks resulted in 7,613 residents with ILI, 793 hospitalisations and 338 deaths. NSW outbreaks had a median attack rate of 17% and median duration of eight days. Data completeness, which varied considerably between districts, limited the capacity to accurately consider some important epidemiological and policy issues.

Discussion

Influenza outbreaks impose a major burden on the residents and staff of ACFs. Accurate assessment of the year-to-year incidence and severity of influenza outbreaks in these facilities is important for monitoring the effectiveness of outbreak prevention and management strategies. Some key data were incomplete and strategies to improve the quality of these data are needed, particularly for: the number of influenza-related deaths among residents; resident and staff vaccination coverage prior to outbreaks; and recorded use of antiviral prophylaxis.

Impact of funding on influenza vaccine uptake in Australian children

Objectives and importance of study: Young children are at higher risk for serious influenza outcomes but, historically, Australian children aged less than 5 years have had low seasonal influenza vaccine uptake. In 2018, most Australian jurisdictions implemented funded influenza vaccine programs targeted at improving vaccine uptake in this age group. Our aim was to determine how successful these programs were at improving self-reported seasonal influenza vaccine uptake at the community level by comparing vaccination rates in each Australian jurisdiction before and after the introduction of funded vaccines for children aged 6 months to less than 5 years, as well as other age groups.

STUDY TYPE

Volunteer observational cohort study.

METHODS

Flutracking is an email-based surveillance tool for influenza-like illness that collects information about symptoms and influenza vaccination. We used historical data from 2014 to 2017 to estimate baseline vaccination status before funding of childhood influenza vaccines was introduced. We compared self-reported vaccine uptake in children younger than 5 years, children aged 5-17 years and adults (18-64 years, and 65 years and older) in 2018 and 2019 by state or territory. Mixed effects logistic regressions were used to measure the association between vaccination and a number of predictors, including whether the child was eligible for free vaccines, and whether adults resided with children or not.

RESULTS

We found large increases in vaccine uptake for children younger than 5 years in 2018 in all jurisdictions except Western Australia (where vaccines were already funded) and the Northern Territory (where funded vaccines were not introduced until 2019) that coincided with vaccine policy changes. Self-reported vaccination rates for young children in 2018 increased 2.7-4.2-fold in jurisdictions that funded the vaccine (compared with the previous, unfunded period). Being eligible for the funded vaccine was associated with much higher odds (odds ratio [OR] 4.75; 95% confidence interval [CI] 4.57, 4.79) of a young child being vaccinated. Older children and adults younger than 65 years were also more likely to receive the vaccine following policy changes.

CONCLUSION

The seasonal influenza vaccine is an important protective measure for those at risk of serious outcomes, including young children. Flutracking data demonstrates that government-funded vaccines can lead to an almost five-fold increase in self-reported vaccine uptake of the targeted age group, as well as previously unreported flow-on effects to older children. This suggests that funded vaccines for young children may encourage caregivers to also vaccinate themselves and their older children.

Identifying early changes in influenza vaccination uptake following a government funded immunisation program using a participatory community surveillance program

Following Australia’s severe influenza season in 2017, the health departments of the states and territories commenced funding in 2018 of influenza vaccine for all children aged six months to five years. As the national immunisation register has recently been extended to include recording of vaccination for all age groups, Australia’s community-based influenza-like illness (ILI) surveillance system, Flutracking, was used to explore influenza vaccine coverage in participants. Flutracking participants respond to a weekly survey about ILI from April to October each year. Participants report their influenza vaccine status with the current year’s vaccine in the first weekly survey, and if unvaccinated (or unknown), participants are prompted with the question weekly until the end of the Flutracking season. Detailed methods for Flutracking are available elsewhere.1 Self-reported vaccine coverage by age group (<5 years, 5 to 17 years, 18 to 64 years and ≥65 years) was calculated at 21 October (timing of the final 2018 Flutracking survey) for participants who had completed at least one survey in 2018. The five-year average was calculated for the percentage vaccinated at the end of the Flutracking survey for the years 2013 to 2017, and compared to 2018. Flutracking received ethics approval from the University of Newcastle (# 06/03/22.403) in 2006. In 2009 the program applied to the University of Newcastle to exit the ethics committee review as Flutracking had been incorporated into the national influenza surveillance system. The total number of participants completing at least one survey increased from 18,437 in 2013 to 45,532 in 2018. Flutracking participants are more likely to be female (59.8% compared to 50.4%) and more likely to have completed a postgraduate degree (22.6% compared to 3.6%) than the general Australian population.2 A relatively large proportion of Flutracking participants are health care workers, working face to face with patients (17.5%). Keywords: flutracking, vaccine coverage, influenza vaccine, influenza like illness, community based surveillance

Enablers of innovation in digital public health surveillance: lessons from Flutracking

Opportunities for digital innovation in public health surveillance have never been greater. Social media data streams, Open Data initiatives, mHealth geotagged data, and the 'internet of things' are ripe for development. To embrace these opportunities we need to provide public health professionals with environments that support experimentation with new technology. Innovative practitioners will lead discovery, adaption, trialling and deployment of new technological solutions mostly developed outside their organisation. To enhance innovation agencies will need to learn from 'startup culture' and the practices of large organisations that ring fence innovative teams to protect them and allow them to 'break rules', 'fail fast', and innovate.

Flutracking weekly online community survey of influenza-like illness annual report, 2015

Flutracking is a national online community influenza-like illness (ILI) surveillance system that monitors weekly ILI activity and impact in the Australian community. This article reports on the 2015 findings from Flutracking. From 2014 to 2015 there was a 38.5% increase in participants to 27,824 completing at least 1 survey with a peak weekly response of 25,071 participants. The 2015 Flutracking national ILI weekly fever and cough percentages peaked in late August at 5.0% in the unvaccinated group, in the same week as the national counts of laboratory confirmed influenza peaked. A similar percentage of Flutracking participants took two or more days off from work or normal duties in 2015 (peak level 2.3%) compared with 2014 (peak level 2.5%) and the peak weekly percentage of participants seeking health advice was 1.6% in both 2014 and 2015. Flutracking fever and cough peaked in the same week as Influenza Complications Alert Network surveillance system influenza hospital admissions. The percentage of Flutracking participants aged 5 to 19 years with cough and fever in 2015 was the highest since 2011. The 2015 season was marked by a transition to predominantly influenza B strain circulation, which particularly affected younger age groups. However, for those aged 20 years and over, the 2015 national Flutracking influenza season was similar to 2014 in community ILI levels and impact.

Flutracking weekly online community survey of influenza-like illness: 2013 and 2014

Flutracking is a national online community influenza-like illness (ILI) surveillance system that monitors weekly ILI activity and field vaccine effectiveness. This article reports on the 2013 and 2014 findings from Flutracking. From 2013 to 2014 there was a 14.0% increase in participants who completed at least 1 survey to 21,021 participants. By the end of the 2013 and 2014 seasons, respectively 59.7% and 59.1% of all participants had received the seasonal influenza vaccine. The 2013 Flutracking national ILI weekly incidence peaked in late August at 4.3% in the unvaccinated group, 1 week earlier than national counts of laboratory confirmed influenza. The 2014 Flutracking national ILI weekly incidence also peaked in late August at 4.7% in the unvaccinated group, in the same week as national counts of laboratory confirmed influenza. A lower percentage of Flutracking participants took two or more days off from work or normal duties in 2013 (peak level 1.6%) compared with 2014 (peak level 2.5%) and sought health advice in 2013 (peak level of 1.1%) compared with 2014 (peak of 1.6%). Flutracking ILI surveillance suggests that 2014 was a moderately more intense season than 2013 and similar to 2012.

Building influenza surveillance pyramids in near real time, Australia

A timely measure of circulating influenza virus severity has been elusive. Flutracking, the Australian online influenza-like illness surveillance system, was used to construct a surveillance pyramid in near real time for 2011/2012 participants and demonstrated a striking difference between years. Such pyramids will facilitate rapid estimation of attack rates and disease severity.

Flutracking weekly online community survey of influenza-like illness annual report 2011 and 2012

Flutracking is a national online community influenza-like illness (ILI) surveillance system that monitors weekly ILI activity and field vaccine effectiveness (FVE). This article reports on the 2011 and 2012 findings from Flutracking. There was a 22% increase in participants to 16,046 who completed at least one survey in 2012, compared with 2011 (13,101). By October 2012 (the end of the 2012 season), 54.2% of participants had received the 2012 seasonal vaccine, while by the end of the 2011 season, 55.9% of participants had received the 2011 seasonal vaccine. From 2007 to 2012 the FVE calculation for New South Wales participants demonstrated that the seasonal vaccine was effective except in 2009 when a novel H1N1 virus was dominant. The 2012 Flutracking ILI weekly incidence peaked in mid-July at 4.9% in the unvaccinated group, 1 month earlier than laboratory confirmed influenza. The 2011 Flutracking ILI weekly incidence peaked in mid-August at 4.1% in the unvaccinated group, 1 week later than laboratory confirmed influenza. Similar to laboratory notifications, there was an increase in ILI activity from 2010 to 2012, with the peak weekly ILI prevalence for 2012 Flutracking data, (unstratified by vaccination status), being higher (4.7%) than the peak weekly prevalence for 2011 (3.8%) and 2010 (3.7%). The 2012 Flutracking influenza season showed moderate levels of ILI, compared with lower levels of ILI seen in 2011 and 2010, and consistent with the increase in national influenza laboratory notifications.

The media and public health: complexity, controversy and combat

Public health officials and the media in conflict in their "shadow" roles .

Flutracking weekly online community survey of influenza-like illness annual report, 2010

Flutracking is a national weekly online survey of influenza-like illness (ILI) completed by community members. Flutracking integrates participants' ILI symptom information with their influenza vaccination status to monitor influenza activity and field vaccine effectiveness (FVE). This report summarises results from the 2010 Flutracking season compared with previous seasons. Nationally, participation in Flutracking has more than doubled between 2008 and 2010, with 5,346 new participants enrolled or recruited in 2010 and a peak weekly participation of 10,773. By the end of the 2010 season, 5,904 of 9,109 (64.8%) participants had received the monovalent pandemic vaccine and/or the 2010 seasonal vaccine. From 2007 to 2010 FVE calculations demonstrated that the seasonal vaccine was effective except in 2009 during the pandemic. Peak 2010 ILI activity occurred in early June and August, and peak weekly 2010 ILI rates (4.2% among unvaccinated participants) were lower than the peak ILI rates during the 2009 pandemic (6.0% among unvaccinated participants). However, the decrease in laboratory notifications was much larger than the decrease in Flutracking rates. In summary, the number of Flutracking participants continued to steadily increase over the 2010 influenza season. The system has shown value in providing weekly vaccination uptake data during and beyond the 2009 influenza pandemic, as well as rapid FVE estimates that are qualitatively aligned with findings from other analyses of vaccine efficacy. Flutracking has also provided estimates of weekly community ILI activity that were not biased by health seeking behaviour and clinician testing practices.

Online Flutracking survey of influenza-like illness during pandemic (H1N1) 2009, Australia

We compared the accuracy of online data obtained from the Flutracking surveillance system during pandemic (H1N1) 2009 in Australia with data from other influenza surveillance systems. Flutracking accurately identified peak influenza activity timing and community influenza-like illness activity and was significantly less biased by treatment-seeking behavior and laboratory testing protocols than other systems.

A structured framework for improving outbreak investigation audits

Background

Outbreak investigation is a core function of public health agencies. Suboptimal outbreak investigation endangers both public health and agency reputations. While audits of clinical medical and nursing practice are conducted as part of continuous quality improvement, public health agencies rarely make systematic use of structured audits to ensure best practice for outbreak responses, and there is limited guidance or policy to guide outbreak audit.

Methods

A framework for prioritising which outbreak investigations to audit, an approach for conducting a successful audit, and a template for audit trigger questions was developed and trialled in four foodborne outbreaks and a respiratory disease outbreak in Australia.

Results

The following issues were identified across several structured audits: the need for clear definitions of roles and responsibilities both within and between agencies, improved communication between agencies and with external stakeholders involved in outbreaks, and the need for development of performance standards in outbreak investigations - particularly in relation to timeliness of response. Participants considered the audit process and methodology to be clear, useful, and non-threatening. Most audits can be conducted within two to three hours, however, some participants felt this limited the scope of the audit.

Conclusion

The framework was acceptable to participants, provided an opportunity for clarifying perceptions and enhancing partnership approaches, and provided useful recommendations for approaching future outbreaks. Future challenges include incorporating feedback from broader stakeholder groups, for example those of affected cases, institutions and businesses; assessing the quality of a specific audit; developing training for both participants and facilitators; and building a central capacity to support jurisdictions embarking on an audit. The incorporation of measurable performance criteria or sharing of benchmark performance criteria will assist in the standardisation of outbreak investigation audit and further quality improvement.

ASPREN surveillance system for influenza-like illness - A comparison with FluTracking and the National Notifiable Diseases Surveillance System

BACKGROUND

General practitioners play an important role in the detection and clinical management of influenza. The Australian Sentinel Practice Research Network (ASPREN) has been collecting data from sentinel GPs on selected conditions, including influenza-like illness (ILI), since 1991 to inform public health authorities of communicable disease activity in the community.

METHODS

Weekly incidence of ILI data reported by ASPREN GPs in 2007-2008 was compared with data from two separate surveillance systems: New South Wales data from FluTracking, an online self reporting ILI surveillance system; and national laboratory notifications of influenza reported to the National Notifiable Diseases Surveillance System between 2003 and 2008.

RESULTS

ASPREN recorded peak ILI rates of 47 per 1000 consultations in week 30 (ending 29 July) 2007 and 34 per 1000 consultations in week 36 (ending 7 September) 2008. Similar trends in incidence were seen in FluTracking cough and fever rates, ASPREN data in New South Wales and National Notifiable Diseases Surveillance System laboratory notifications.

DISCUSSION

Data captured by the three separate surveillance systems provide complementary information regarding influenza in the Australian population.

Flutracking surveillance: comparing 2007 New South Wales results with laboratory confirmed influenza notifications

General practice and hospital surveillance for influenza-like illness (ILI) and laboratory influenza surveillance provide useful but incomplete information on influenza incidence. Flutracking is an Australian pilot of an Internet-based community ILI syndromic surveillance system designed to detect inter-pandemic and, potentially, pandemic influenza. Presence of fever and/or cough and absence from normal duties are collected weekly. Influenza vaccination status of respondents is recorded. New South Wales Flutracking data for 2007 were compared with New South Wales laboratory notifications for confirmed influenza to validate it's ability to provide alerts of influenza activity. Symptom rates amongst vaccinated and unvaccinated Flutracking respondents were compared using a variety of case definitions, with New South Wales laboratory influenza notifications. Time series methods were used to estimate the degree of correlation between each Flutracking case definition and the laboratory data. For the unvaccinated group, the correlations between all Flutracking case definitions and laboratory data were statistically significant, while for the vaccinated group no case definitions were significantly correlated with laboratory data. Thus Flutracking ILI data amongst unvaccinated participants correlated well with influenza laboratory surveillance.

Likely impact of school and childcare closures on public health workforce during an influenza pandemic: a survey

During an influenza pandemic, public health staff may not report to work due to illness, transport disruptions or care responsibilities, including care of children if school closures occur. A survey was conducted in a population health unit to estimate the impact of closure of schools and day care facilities on staff ability to work at their usual workplace or at home, and determine their access to the Internet for communication. Staff were also asked about concerns associated with working from home. Eighty-seven staff completed a paper based survey. Thirty-eight per cent (33/87) of staff may be absent from work due to the impact of childcare and school closure, however 24 (73%) of these staff would be able to work from home with most having access to dial-up (87%) and broadband Internet access (71%). Staff reported concerns about potential exposure to pandemic influenza, the need for personal protection and clearly defined roles and training, availability of adequate equipment and technology to work from home, and sick leave provisions during a pandemic. While school and childcare closures will have a significant impact on public health agency staff, they have the capacity and willingness to work from home. Their practical concerns should be addressed to optimise their participation.

Age-specific risk factors for sporadic Campylobacter infection in regional Australia

In a case-control study in the Hunter region of New South Wales, Australia, 354 cases and 593 controls were recruited to investigate meat, other food, and environmental exposures as potential risk factors for domestically acquired Campylobacter illness. In a multivariable model, illness was significantly associated with household exposure to diarrheal illness, consumption of restaurant chicken or beef, eating two or more "fast" food meals in a week, and overseas travel. Comparing exposures for the 0- to 4-year and 5-year and older age groups allowed detection of additional risk factors. Eating restaurant-prepared red meat and swimming were significantly associated with Campylobacter illness in the older group only. These findings demonstrate age-specific differences in risk factors for campylobacteriosis.

Business continuity management and pandemic influenza

Pandemic influenza planning presents challenges for both government and businesses. Effective cooperation and communication before and during a pandemic will help mitigate the major threats to societal function. The major challenges for government include communicating a realistic estimate of pandemic risk, managing community anxiety, communicating the need for rationing of vaccines and antiviral medications, setting standards for preparedness, and gaining the trust of essential service workers. For businesses the challenges are tailoring generic planning guides to local use, and making links with local and regional partners in pandemic planning.

Use of a geographic information system to track smelter-related lead exposures in children: North Lake Macquarie, Australia, 1991-2002

BACKGROUND

To determine patterns of childhood lead exposure in a community living near a lead and zinc smelter in North Lake Macquarie, Australia between 1991 and 2002.

METHODS

An analysis of serial blood lead levels (BLL) of children less than 13 years of age in North Lake Macquarie participating in voluntary blood lead screening. Distance to the smelter and soil lead concentration of the child's place of residence was calculated. Categorical analysis of BLL by residential distance from smelter, residential soil lead concentration, age and year of sample was calculated. Linear regression models were fit for blood lead levels against residential distance from smelter, the log of residential soil lead concentration, age and year of BLL sample.

RESULTS

Geometric mean BLLs were statistically significantly higher for distances less than 1.5 kilometres from the smelter and for residential soil lead concentrations greater than 300 ppm. Yearly BLLs since 1995 were statistically significantly lower than for preceding years, with an average decrease of 0.575 microg/dL per year since 1991. BLLs are statistically significantly higher for children whose age is 1 to 3 years old. Linear regression modelling of BLL predicted a statistically significant decrease in BLL of 3.0831 microg/dL per kilometre from the smelter and a statistically significant increase in BLL of 0.25 microg/dL per log of lead in residential soil. The model explained 28.2% of the variation in BLL.

CONCLUSION

Residential distance to the smelter, log of residential soil lead concentration, child's age and year of BLL sample are statistically significant factors for predicting elevated BLLs in children living near a North Lake Macquarie lead smelter.

Sesame seed products contaminated with Salmonella: three outbreaks associated with tahini

In November 2002, the first of three outbreaks of Salmonella Montevideo infection in Australia and New Zealand was identified in New South Wales, Australia. Affected persons were interviewed, and epidemiologically linked retail outlets inspected. Imported tahini was rapidly identified as the source of infection. The contaminated tahini was recalled and international alerts posted. A second outbreak was identified in Australia in June-July 2003 and another in New Zealand in August 2003. In a total of 68 S. Montevideo infections, 66 cases were contacted. Fifty-four (82%) reported consumption of sesame seed-based foods. Laboratory analyses demonstrated closely related PFGE patterns in the S. Montevideo isolates from human cases and sesame-based foods imported from two countries. On the basis of our investigations sesame-based products were sampled in other jurisdictions and three products in Canada and one in the United Kingdom were positive for Salmonella spp., demonstrating the value of international alerts when food products have a wide distribution and a long shelf life. A review of the controls for Salmonella spp. during the production of sesame-based products is recommended.

Foodborne disease outbreaks in Australia, 1995 to 2000

Health agencies are increasingly conducting systematic reviews of foodborne disease outbreak investigations to develop strategies to prevent future outbreaks. We surveyed state and territory health departments to summarise the epidemiology of foodborne disease outbreaks in Australia from 1995 to 2000. From 1995 through 2000, 293 outbreaks were identified, with 214 being of foodborne origin. One hundred and seventy-four (81%) had a known aetiology, and accounted for 80 per cent (6,472/8,124) of illnesses. There were 20 deaths attributed to foodborne illness. Of the 214 outbreaks, bacterial disease was responsible for 61 per cent of outbreaks, 64 per cent of cases and 95 per cent of deaths. The most frequent aetiology of outbreaks was Salmonella in 75 (35%) outbreaks, Clostridium perfringens in 30 (14%), ciguatera toxin in 23 (11%), scombrotoxin in 7 (3%) and norovirus in 6 (3%). Salmonellosis was responsible for eight of the 20 (40%) deaths, as was Listeria monocytogenes. Restaurants and commercial caterers were associated with the highest number of outbreak reports and cases. Outbreaks in hospitals and aged care facilities were responsible for 35 per cent of deaths. The most frequently implicated vehicles in the 173 outbreaks with known vehicles were meats 64 (30%), fish 34 (16%), seafood 13 (6%), salad 12 (6%), sandwiches 11 (5%) and eggs 9 (4%). Chicken, the most frequently implicated meat, was associated with 27 (13%) outbreaks. This summary demonstrates the serious nature of foodborne disease and supports the move to risk-based food safety interventions focusing on mass catering and hospital and aged care facilities.

An outbreak of gastrointestinal illness associated with the consumption of escolar fish

An outbreak of gastrointestinal illness occurred amongst attendees of a conference lunch in the Hunter area, New South Wales, in October 2001. A distinctive symptom reported by many ill persons was the presence of oily diarrhoea. The Hunter Public Health Unit investigated the outbreak by conducting a telephone interview of the cohort of conference attendees using a standard questionnaire. Twenty persons out of 44 attendees (46%) became ill following the conference. The median incubation period was 2.5 hours (range 1-90 hours). The most common symptoms reported were; diarrhoea (80%)-38 per cent of these reported oily diarrhoea; abdominal cramps (50%); nausea (45%); headache (35%) and vomiting (25%). For analyses, a case was defined as a person who developed oily diarrhea, or diarrhoea within 48 hours, or had at least two other symptoms of gastroenteritis within 6 hours, of the conference lunch. Seventeen persons had symptoms that met the case definition. None of the foods or beverages consumed were significantly associated with illness, however, all cases had consumed fish and none of those who did not eat fish (4 persons) became ill. Moreover, only 'fish' or 'potato chips' could explain a significant proportion of the illness. Analysis of the oil composition of the fish consumed was consistent with the known profile of the species marketed as 'escolar'. Among those who consumed fish the following potential risk factors did not have a significant association with the illness; Body Mass Index, age, health status and the amount of fish consumed. We concluded that consumption of fish within the marketing group escolar can cause severe abdominal cramping, nausea and vomiting, in addition to incontinent diarrhoea.

Outbreaks of enterotoxigenic Escherichia coli infection in American adults: a clinical and epidemiologic profile

Because enterotoxigenic Escherichia coli (ETEC) is not identified by routine stool culture methods, ETEC outbreaks may go unrecognized, and opportunities for treatment and prevention may be missed. To improve recognition of adult ETEC outbreaks, we compared them with reported outbreaks of viral gastroenteritis. During 1975-95, we identified 14 ETEC outbreaks in the United States and 7 on cruise ships, caused by 17 different serotypes and affecting 5683 persons. Median symptom prevalences were: diarrhoea 99%, abdominal cramps 82%, nausea 49%, fever 22%, vomiting 14%. The median incubation period was 42 h, and for 8 of 10 outbreaks, the mean or median duration of illness was > 72 h (range 24-264). For 17 (81%) ETEC outbreaks, but for only 2 (8%) viral outbreaks, the prevalence of diarrhoea was > or = 2.5 times the prevalence of vomiting. ETEC outbreaks may be differentiated from viral gastroenteritis outbreaks by a diarrhoea-to-vomiting prevalence ratio of > or = 2.5 and a longer duration of illness.

A retrospective search for lyssavirus in humans in the Northern Territory

BACKGROUND

Following the 1996 discovery of a rabies-like lyssavirus in Australian flying foxes, it was unclear whether this was a new epizootic or an unrecognised, previously existing disease.

OBJECTIVE

To review cases of unexplained encephalitis in the Northern Territory (NT) to test available clinical specimens for lyssavirus and survey the use of diagnostic tests by clinicians.

METHODS

The NT hospital morbidity database was searched from January 1992 to September 1996 for all Royal Darwin Hospital (RDH) cases with an ICD-9 code encompassing encephalitis or viral meningitis. Final diagnoses were determined by hospital record review. For cases of unexplained encephalitis, we assessed the use of diagnostic tests and located clinical specimens for testing for lyssavirus-specific inclusion bodies via immunohistochemistry, immunofluorescence and reverse-transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Encephalitis occurred in 34/154 (22%) cases located by the search; 53% (18/34) of encephalitis cases were unexplained. Of these, 24% had no serology performed and 47% had no blood cultures taken. Four (22%) died and two had autopsies. These were the only two cases with clinical specimens available for testing. They were negative for lyssavirus. None of the 71 cases coded as viral meningitis had unexplained encephalitis.

CONCLUSION

There was a considerable proportion of unexplained illness among NT cases of encephalitis.

IMPLICATIONS

Clinicians should test for lyssavirus in patients with encephalitic symptoms and a postmortem should be sought where death is unexplained. Specimens should be stored to enable testing for emerging infectious diseases.

Timeliness of Salmonella notifications in South Australia

OBJECTIVE

To evaluate the timeliness of Salmonella serotype and phage type notifications in South Australia.

METHOD

We surveyed all notifications of Salmonella to the South Australian Department of Human Services between July 1995 and June 1996. We entered data onto an Epi Info 6.02 database and calculated the time interval between various stages of typing notification.

RESULTS

The median time taken between collection of a faecal specimen and receipt of serotype notification was 10 days (range, 5-38), while phage type notification took a further seven days (range 0-40). The time interval between collection of a specimen and notification of a Salmonella final identity was 14 days (range 6-49). The internal mail system of the Department of Human Services delayed notification a median of two days. Environmental Health Officers supplied reports for 224 (58%) of 384 cases, 71% of which occurred before the final Salmonella isolate was known.

CONCLUSIONS

We found that the internal departmental mail system delayed the notification of Salmonella. In South Australia, investigations should focus on clusters of cases of known Salmonella identity, rather than all notified cases.

IMPLICATIONS

To improve communicable disease investigations, health agencies should evaluate the timeliness of surveillance systems and examine the feasibility of transferring laboratory data electronically.

Diagnosis and treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common medical disorder characterized by symptoms of abdominal pain and bowel dysfunction. It is associated with significant disability and health care costs. A practical approach to diagnosis is the symptom-based Rome criteria. Management of patients has been helped by recent findings relating to the epidemiology, pathophysiology and psychosocial contributions of the disorder. Dysregulation of intestinal motor, sensory and central nervous system function is currently believed to be the basis for IBS symptoms. Symptoms are due to both abnormal intestinal motility and enhanced visceral sensitivity. Psychosocial factors are not a cause but can affect the illness experience and clinical outcome. Finally, treatment involves an effective physician-patient relationship and an integrated pharmacologic and behavioral approach that is determined by the needs of the patient, the type and severity of the symptoms and the degree of disability.

A cost-effectiveness analysis of directly observed therapy vs self-administered therapy for treatment of tuberculosis

STUDY OBJECTIVES

To compare the costs and effectiveness of directly observed therapy (DOT) vs self-administered therapy (SAT) for the treatment of active tuberculosis.

DESIGN

Decision analysis.

SETTING

We used published rates for failure of therapy, relapse, and acquired multidrug resistance during the initial treatment of drug-susceptible tuberculosis cases using DOT or SAT. We estimated costs of tuberculosis treatment at an urban tuberculosis control program, a municipal hospital, and a hospital specializing in treating drug-resistant tuberculosis.

OUTCOME MEASURES

The average cost per patient to cure drug-susceptible tuberculosis, including the cost of treating failures of initial treatment.

RESULTS

The direct costs of initial therapy with DOT and SAT were similar ($1,206 vs $1,221 per patient, respectively), although DOT was more expensive when patient time costs were included. When the costs of relapse and failure were included in the model, DOT was less expensive than SAT, whether considering outpatient costs only ($1,405 vs $2,314 per patient treated), outpatient plus inpatient costs ($2,785 vs $10,529 per patient treated), or outpatient, inpatient, and patients' time costs ($3,999 vs $12,167 per patient treated). Threshold analysis demonstrated that DOT was less expensive than SAT through a wide range of cost estimates and clinical event rates.

CONCLUSION

Despite its greater initial cost, DOT is a more cost-effective strategy than SAT because it achieves a higher cure rate after initial therapy, and thereby decreases treatment costs associated with failure of therapy and acquired drug resistance. This cost-effectiveness analysis supports the widespread implementation of DOT.

Diagnosis and treatment of irritable bowel syndrome

Irritable bowel syndrome is a common disorder characterized by symptoms of abdominal pain with diarrhea and/or constipation. It is associated with significant disability and health care costs. A practical approach to diagnosis utilizes the symptom-based Rome criteria. Management of patients has been helped by recent findings relating to the pathophysiology of the disorder. Dysregulation of intestinal motor functions, sensory functions and central nervous system functions is currently believed to be the basis for irritable bowel symptoms. Symptoms are a result of both abnormal intestinal motility and enhanced visceral sensitivity. Psychosocial factors can affect the illness experience and the clinical outcome. An effective physician-patient relationship is required for a successful outcome. Individualized treatment involves an integrated pharmacologic and behavioral approach determined by the predominant symptom type, the severity of the symptoms and the degree of disability.

An outbreak of gastroenteritis and fever due to Listeria monocytogenes in milk

BACKGROUND

After an outbreak of gastroenteritis and fever among persons who attended a picnic in Illinois, chocolate milk served at the picnic was found to be contaminated with Listeria monocytogenes.

METHODS

In investigating this outbreak, we interviewed the people who attended the picnic about what they ate and their symptoms. Surveillance for invasive listeriosis was initiated in the states that receive milk from the implicated dairy. Stool and milk samples were cultured for L. monocytogenes. Serum samples were tested for IgG antibody to listeriolysin O.

RESULTS

Forty-five persons had symptoms that met the case definition for illness due to L. monocytogenes, and cultures of stool from 11 persons yielded the organism. Illness in the week after the picnic was associated with the consumption of chocolate milk. The most common symptoms were diarrhea (present in 79 percent of the cases) and fever (72 percent). Four persons were hospitalized. The median incubation period for infection was 20 hours (range, 9 to 32), and persons who became ill had elevated levels of antibody to listeriolysin O. Isolates from stool specimens from patients who became ill after the picnic, from sterile sites in three additional patients identified by surveillance, from the implicated chocolate milk, and from a tank drain at the dairy were all serotype 1/2b and were indistinguishable on multilocus enzyme electrophoresis, ribotyping, and DNA macrorestriction analysis.

CONCLUSIONS

L. monocytogenes is a cause of gastroenteritis with fever, and sporadic cases of invasive listeriosis may be due to unrecognized outbreaks caused by contaminated food.

Blood lead levels in radiator repair workers in Colorado

A laboratory-based blood lead surveillance system in Colorado identified radiator repair workers as having the highest blood lead levels of all worker groups reported. A survey of 42 radiator repair shops in ten locales throughout Colorado was undertaken to estimate the prevalence of workers with elevated blood lead levels > 25 micrograms/dL. The survey was designed to test the sensitivity of the surveillance system and to assess working conditions and practices in the radiator repair industry in Colorado. Of 63 workers, 39 (62%) had blood lead levels > 25 micrograms/dL. The sensitivity of the surveillance system for detecting radiator repair workers with elevated blood lead levels was estimated at 11%. None of the radiator repair shops had adequate local exhaust ventilation. Work practice and engineering modifications are needed to reduce lead exposure in this industry.

Foodborne disease: current trends and future surveillance needs in Australia

Review of 128 outbreaks of foodborne disease (affecting almost 6000 people, with six deaths) between 1980 and 1995 and available surveillance data showed that foodborne disease in Australia is similar to that in other industrialised countries. Campylobacter spp. and non-typhoidal Salmonella spp. were the most commonly reported pathogens. However, Australia, unlike the UK and US, lacks a comprehensive national surveillance system for foodborne diseases. This is essential to improve control of these diseases.

The cost of a food-borne outbreak of hepatitis A in Denver, Colo

BACKGROUND

In 1992, a food-borne outbreak of hepatitis A associated with a catering facility in Denver, Colo, resulted in 43 secondary cases of hepatitis A and the potential exposure of approximately 5000 patrons.

OBJECTIVES

To assess (1) disease control costs, including state and local health department personnel costs, provision and administration of immune globulin, and cost of extra hepatitis A serologic tests performed; (2) business losses; and (3) cost of the cases' illnesses.

METHODS

Cost data were collected from hospitals, health maintenance organizations, health departments, laboratories, the caterer's insurance company, and the catering facility involved in the outbreak.

RESULTS

The total costs assessed in the outbreak from a societal perspective were $809,706. Disease control costs were $689,314, which included $450,397 for 16,293 immune globulin injections and $105,699 for 2777 hours of health department personnel time. The cases' medical costs were $46,064, or 7% of the disease control costs.

CONCLUSIONS

The cases' medical costs and productivity losses were only a minor component of the total cost of this outbreak. The high cost of food-borne outbreaks should be taken into account in economic analyses of the vaccination of food handlers with inactivated hepatitis A vaccine.