Historical data and modern methods reveal insights in measles epidemiology: a retrospective closed cohort study

OBJECTIVES Measles was endemic in England during the early 1800s; however, it did not arrive in Australia until 1850 whereas other infectious diseases were known to have arrived much earlier-many with the First Fleet in 1788-leading to the question of why there was a difference. DESIGN Ships surgeons' logbooks from historical archives, 1829-1882, were retrospectively reviewed for measles outbreak data. Infectious disease modelling techniques were applied to determine whether ships would reach Australia with infectious measles cases. SETTING Historical ship surgeon logbooks of measles outbreaks occurring on journeys from Britain to Australia were examined to provide new insights into measles epidemiology. PRIMARY AND SECONDARY OUTCOME MEASURES Serial intervals and basic reproduction numbers (R(0)), immunity, outbreak generations, age-distribution, within-family transmission and outbreak lengths for measles within these closed cohorts. RESULTS Five measles outbreaks were identified (163 cases). The mean serial interval (101 cases) was 12.3 days (95% CI 12.1 to 12.5). Measles R(0) (95 cases) ranged from 7.7-10.9. Immunity to measles was lowest among children ≤10 years old (range 37-42%), whereas 94-97% of adults appeared immune. Outbreaks ranged from 4-6 generations and, before 1850, were 41 and 38 days in duration. Two outbreaks after 1850 lasted longer than 70 days and one lasted 32 days. CONCLUSIONS Measles syndrome reporting in a ship surgeon's logs provided remarkable detail on prevaccination measles epidemiology in the closed environment of ship voyages. This study found lower measles R(0) and a shorter mean clinical serial interval than is generally reported. Archival ship surgeon log books indicate it was unlikely that measles was introduced into Australia before 1850, owing to high levels of pre-existing immunity in ship passengers, low numbers of travelling children and the journey's length from England to Australia.g BP was supported by a Master of Applied Epidemiology scholarship from the Australian Government and a Hunter Medical Research Institute Research Fellowshi

Validation of questions designed for investigation of gastroenteritis

Background: Health departments routinely investigate cases of gastroenteritis through interviews to determine the source of infection. However, validation studies of dietary questionnaires typically focus on quantities consumed and don't assess questions designed to identify sources of foodborne illness. We aimed to assess the accuracy and reliability of information collected by surveys of food history recall for gastroenteritis investigations. Methods: A questionnaire was developed to investigate the sources of foodborne gastroenteritis in Australia, with questions on food exposures selected for validation. Fifty-five participants photographed all foods consumed and food receipts obtained during a seven-day observation period. These photographs were uploaded to an online survey or emailed to the researcher. Participants were contacted 14 days later for a telephone interview about foods consumed in the seven-day period. Questionnaire responses were compared to uploaded photographs. Kappa statistics (κ) and 95% confidence intervals were calculated. Sixty-two questions were assessed, including those targeting foods considered high-risk for foodborne gastroenteritis. Potential risk factors covered by these questions included: meats (poultry, beef, pork, and deli meats), the state of poultry purchased (raw versus precooked), and the number of meals eaten outside of the home. Results: Several questions targeting high-risk foods were found to have substantial-to-almost perfect agreement (κ ≥ 0.610) between what was eaten and what was reported by participants, with most questions showing at least a moderate level of agreement (κ = 0.410–0.600). Questions regarding exposure to different types of meat showed a high level of consistency. The only question with poor participant recall (κ < 0.000) was that relating to consumption of undercooked beef or veal. Conclusion: Several questions designed for investigation of gastroenteritis were found to provide at least a moderate level of accurate and reliable recall, even after a delay until interview. These questions are suitable for investigating sources of foodborne gastroenteritis

Mesothelioma trends in the ACT and comparisons with the rest of Australia

OBJECTIVES Inhalation of asbestos fibres is the predominant cause of malignant mesothelioma. Domestic exposure to asbestos is a major community concern in the Australian Capital Territory (ACT) because of loose-fill asbestos home insulation. Little is known about how trends in mesothelioma rates in the ACT compare with those elsewhere. The objective of this study was to describe trends in mesothelioma rates in the ACT and compare them with those for the rest of Australia. METHODS We used de-identified data from the ACT Cancer Registry (1982- 2014), and the Western Australia (WA) Cancer Registry and the Australian Cancer Database (1982-2011). We calculated crude mesothelioma rates, by 3-year periods, for the ACT and for the rest of Australia (excluding WA). We used Poisson regression to analyse mesothelioma trends from 1994 to 2011 (complete reporting period) using an indirect standardisation approach to adjust for age and sex. RESULTS There were 140 mesothelioma cases reported to the ACT Cancer Registry between 1982 and 2014 - 81% male and 19% female. Between 1994 and 2011, age- and sex-adjusted mesothelioma rates in the ACT increased over time, on average by 12% per 3-year period (relative risk [RR] 1.12; 95% confidence interval [CI] 0.99, 1.26). Compared with the rest of Australia (excluding WA), ACT rates were, on average, lower (RR 0.84; 95% CI 0.69, 1.02), but they increased at a higher rate (RR 1.12 per 3-year period; 95% CI 0.99, 1.27). These results are strongly influenced by the higher rate of mesothelioma observed in the ACT in 2009-2011, when ACT rates became similar to those for the rest of Australia (excluding WA). CONCLUSIONS Although mesothelioma rates may have increased more in the ACT than the rest of Australia (excluding WA) during the past two decades, there is considerable uncertainty in the trends. More information is needed regarding the health risks associated with living in a house with loose-fill asbestos insulation. This is the subject of further studies within the ACT Asbestos Health Study.Includes Appendix table: Number of mesothelioma cases and person-years (PY) by sex, age group and year, ACT, 1982 to 201

Population-Attributable Risk Estimates for Risk Factors Associated with Campylobacter Infection

In 2001-2002, a multicenter, prospective case-control study involving 1,714 participants ≥5 years of age was conducted in Australia to identify risk factors for Campylobacter infection. Adjusted population-attributable risks (PARs) were derived for eac

Internationally Distributed Frozen Oyster Meat Causing Multiple Outbreaks of Norovirus Infection in Australia.

Background. Between November 2003 and January 2004, outbreaks of norovirus in 3 Australian jurisdictions involving 83 cases of illness were associated with imported oyster meat. Methods. Cohort studies were conducted in 2 jurisdictions to identify relative risks of illness for the consumption of oysters. A case series was conducted in the third jurisdiction. Results. The cohort studies conducted in the first 2 jurisdictions identified relative risks of illness of 17 (95% confidence interval, 5-51) and 35 (95% confidence interval, 5-243), respectively, for the consumption of oysters. Multiple strains of norovirus were detected in fecal specimens from 8 of 14 patients and in 1 of the 3 batches of implicated oyster meat using seminested reverse-transcriptase polymerase chain reaction methods. Traceback investigations revealed that all oyster meat was harvested from the same estuary system in Japan within the same month. Conclusions. These outbreaks demonstrate the potential of foodborne disease to spread internationally and the need for national and international collaboration to investigate such outbreaks. Foodborne illness related to norovirus is underestimated because of underreporting of human cases and challenges in laboratory detection of viruses in foods, both of which can delay public health action

A structured framework for improving outbreak investigation audits

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. 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. 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. 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

Aetiology-Specific Estimates of the Global and Regional Incidence and Mortality of Diarrhoeal Diseases Commonly Transmitted through Food

Diarrhoeal diseases are major contributors to the global burden of disease, particularly in children. However, comprehensive estimates of the incidence and mortality due to specific aetiologies of diarrhoeal diseases are not available. The objective of this study is to provide estimates of the global and regional incidence and mortality of diarrhoeal diseases caused by nine pathogens that are commonly transmitted through foods.We abstracted data from systematic reviews and, depending on the overall mortality rates of the country, applied either a national incidence estimate approach or a modified Child Health Epidemiology Reference Group (CHERG) approach to estimate the aetiology-specific incidence and mortality of diarrhoeal diseases, by age and region. The nine diarrhoeal diseases assessed caused an estimated 1.8 billion (95% uncertainty interval [UI] 1.1-3.3 billion) cases and 599,000 (95% UI 472,000-802,000) deaths worldwide in 2010. The largest number of cases were caused by norovirus (677 million; 95% UI 468-1,153 million), enterotoxigenic Escherichia coli (ETEC) (233 million; 95% UI 154-380 million), Shigella spp. (188 million; 95% UI 94-379 million) and Giardia lamblia (179 million; 95% UI 125-263); the largest number of deaths were caused by norovirus (213,515; 95% UI 171,783-266,561), enteropathogenic E. coli (121,455; 95% UI 103,657-143,348), ETEC (73,041; 95% UI 55,474-96,984) and Shigella (64,993; 95% UI 48,966-92,357). There were marked regional differences in incidence and mortality for these nine diseases. Nearly 40% of cases and 43% of deaths caused by these nine diarrhoeal diseases occurred in children under five years of age.Diarrhoeal diseases caused by these nine pathogens are responsible for a large disease burden, particularly in children. These aetiology-specific burden estimates can inform efforts to reduce diarrhoeal diseases caused by these nine pathogens commonly transmitted through foods

Population-Attributable Risk Estimates for Risk Factors Associated with Campylobacter Infection, Australia

One-sentence summary: Each year, an estimated 50,500 cases in persons >5 years of age can be directly attributed to consumption of chicken

Estimating Foodborne Gastroenteritis, Australia

An estimated 4.0–6.9 million episodes of foodborne gastroenteritis occur in Australia each year