Using Microsimulation to Estimate the Future Health and Economic Costs of Salmonellosis under Climate Change in Central Queensland, Australia

The Economic Burden of Non-Typhoidal Salmonella and Invasive Non-Typhoidal Salmonella Infection: A Systematic Literature Review

Non-typhoidal Salmonella (NTS) infection and invasive non-typhoidal Salmonella (iNTS) infection cause a significant global health and economic burden. This systematic review aims to investigate the reported economic burden of NTS and iNTS infection, identify research gaps, and suggest future research directions. Data from PubMed and Embase databases up to April 2022 were reviewed, and articles were screened based on predefined criteria. Cost data were extracted, categorized into direct medical costs (DMCs), direct non-medical costs (DNMCs), and indirect costs (ICs), and converted into US dollars (year 2022). Data primarily originated from high-income countries (37 out of 38), with limited representation from Africa and resource-limited settings. For inpatients, DMCs were the primary cost driver for both NTS and iNTS illnesses, with estimates ranging from USD 545.9 (Taiwan, a region of China) to USD 21,179.8 (Türkiye) for NTS and from USD 1973.1 (Taiwan, a region of China) to USD 32,507.5 (United States of America) for iNTS per case. DNMCs and ICs varied widely across studies. Although study quality improved over time, methodological differences persisted. This review underscores the lack of economic data on NTS and iNTS in resource-limited settings. It also highlights the need for economic burden data in resource-limited settings and a standardized approach to generate global datasets, which is critical for informing policy decisions, especially regarding future vaccines.

A methodological framework for ranking communicable and non-communicable diseases due to climate change - A focus on Ireland

There is currently a significant global focus from the public health community on addressing climate-related public health issues. Globally we are witnessing geological shifts, extreme weather events, and the associated incidents that may have a significant human health impact. These include unseasonable weather, heavy rainfall, global sea-level rise and flooding, droughts, tornados, hurricanes, and wildfires. Climate change can have a direct and indirect health impact. The global challenge of climate change requires global preparedness for potential human health effects due to climate change, including vigilance for diseases carried by vectors, foodborne and waterborne diseases, deteriorated air quality, heat stress, mental health, and potential disasters. Therefore, it is essential to identify and prioritise the consequences of climate change to become future-ready. This proposed methodological framework aimed to develop an innovative modelling method using the 'Disability-Adjusted Life Year (DALY)', to rank potential direct and indirect human health impacts (communicable and non-communicable diseases) of climate change. This approach aims to ensure food safety, including water, in the wake of climate change. The novelty of the research will come from developing models with spatial mapping (Geographic Information System or GIS), which will also consider the influence of climatic variables, geographical differences in exposure and vulnerability and regulatory control on feed/food quality and abundance, range, growth, and survival of selected microorganisms. In addition, the outcome will identify and assess emerging modelling techniques and computational-efficient tools to overcome current limitations in climate change research on human health and food safety and to understand uncertainty propagation using the Monte Carlo simulation method for future climate change scenarios. It is envisaged that this research work will contribute significantly to developing a lasting network and critical mass on a national scale. It will also provide a template to implement from a core centre of excellence in other jurisdictions.

Comparison of heat-illness associations estimated with different temperature metrics in the Australian Capital Territory, 2006-2016

While the associations of heat with health outcomes is well researched, there is less consensus on the measures used to define heat exposure and the short-term and delayed impacts of different temperature metrics on health outcomes. We investigate the nonlinear and short-term relationship of three temperature metrics and reported incidence of three gastrointestinal illnesses: salmonellosis, campylobacteriosis and cryptosporidiosis in the Australian Capital Territory (ACT). We also examine the nonlinear association of these illnesses with extreme heat (5th, 75th, 90th percentile of all heat measures). Generalized linear models with Poisson regression accounting for overdispersion, seasonal and long-term trend, weekly number of outbreaks and rainfall were developed for mean and maximum weekly temperature and the heat stress index (EHI_accl). Bacterial illnesses (salmonellosis and campylobacteriosis) showed an overall positive association with extreme heat (75th and 90th percentile of all three heat measures) and an inverse association with low temperature (5th percentile). The shape of the exposure-response curve across a range of temperatures and the lagged effects varied for each disease. Modelling the short-term and delayed effects of heat using different metrics across a range of illnesses can help identify the most appropriate measure to inform local public health intervention planning for heat-related emergencies.

Introducing CASCADEPOP: an open-source sociodemographic simulation platform for us health policy appraisal

Largescale individual-level and agent-based models are gaining importance in health policy appraisal and evaluation. Such models require the accurate depiction of the jurisdiction's population over extended time periods to enable modeling of the development of non-communicable diseases under consideration of historical, sociodemographic developments. We developed CASCADEPOP to provide a readily available sociodemographic micro-synthesis and microsimulation platform for US populations. The micro-synthesis method used iterative proportional fitting to integrate data from the US Census, the American Community Survey, the Panel Study of Income Dynamics, Multiple Cause of Death Files, and several national surveys to produce a synthetic population aged 12 to 80 years on 01/01/1980 for five states (California, Minnesota, New York, Tennessee, and Texas) and the US. Characteristics include individuals' age, sex, race/ethnicity, marital/employment/parental status, education, income and patterns of alcohol use as an exemplar health behavior. The microsimulation simulates individuals' sociodemographic life trajectories over 35 years to 31/12/2015 accounting for population developments including births, deaths, and migration. Results comparing the 1980 micro-synthesis against observed data shows a successful depiction of state and US population characteristics and of drinking. Comparing the microsimulation over 30 years with Census data also showed the successful simulation of sociodemographic developments. The CASCADEPOP platform enables modelling of health behaviors across individuals' life courses and at a population level. As it contains a large number of relevant sociodemographic characteristics it can be further developed by researchers to build US agent-based models and microsimulations to examine health behaviors, interventions, and policies.

Health State Utilities in Children and Adolescents With Osteochondritis Dissecans of the Knee

Background:

The impact of osteochondritis dissecans (OCD) lesions of the knee on a child’s health-related quality of life has not previously been quantified. Preference-based health utility assessment allows patients to assign quality-of-life valuations (utilities) to different health states and conditions.

Purpose:

To determine (1) patient-reported utility scores for health states associated with pediatric OCD lesions of the knee and (2) whether these scores are associated with patient demographics or disease severity.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Children, adolescents, and young adults being treated for OCD of the knee were interviewed to assess utilities for each of the 6 health states commonly encountered in the treatment of OCD: (1) symptomatic lesion, (2) nonoperative rehabilitation, (3) postoperative rehabilitation, (4) intermediate treatment success, (5) early degenerative knee changes, and (6) successful treatment (asymptomatic). Patients were asked to assign health utilities to each state using a standardized feeling thermometer (scale, 0-100), which were converted to a health state utility (scale, 0-1 [1 = perfect health]). Utilities were reported with descriptive statistics, and comparative analyses were performed to test whether assignments were associated with patient age, sex, or whether the OCD lesion required surgical intervention.

Results:

A total of 100 participants treated or undergoing treatment for OCD were prospectively enrolled; 74% were male (n = 74). The median age at the time of survey was 15 years (interquartile range, 13-16.5 years). Utility scores were as follows: symptomatic OCD lesion, 0.15; nonoperative rehabilitation, 0.30; postoperative rehabilitation, 0.30; early degenerative changes, 0.58; intermediate treatment success, 0.65; and successful treatment, 1.0. Utility scores were not associated with age, sex, or whether the participant underwent surgical treatment for the OCD lesion.

Conclusion:

The current study quantified patient-reported utilities for 6 OCD lesion health states, which may be used for future health-related quality of life, decision analysis, and quality/safety/value studies. These utility scores were stable and not affected by patient age, sex, or treatment strategy.

A Successful Technique for the Surface Decontamination of Salmonella enterica Serovar Typhimurium Externally Contaminated Whole Shell Eggs Using Common Commercial Kitchen Equipment

Eggs are a highly nutritious food source used in a wide range of food products. In Australia, eggs are a frequent source of foodborne salmonellosis outbreaks, associated with eggshell contamination with Salmonella enterica serovar Typhimurium (ST). Despite their potentially hazardous nature, raw eggs are often used and consumed in mayonnaise, mousse, ice cream and eggnog. The aim of this study was to develop a shell egg decontamination method that removed ST contamination from the outside of an egg without impacting its usability. The decontamination method was developed by the adaptation of a temperature-controlled water bath (commonly present in kitchens and associated with the sous-vide technique) for the surface decontamination of eggs. The outside of whole eggs was artificially inoculated with two ST strains. The eggs were decontaminated by placing in a sous-vide cooker with the water heated to 57°C. The remaining viable ST present on the whole shell egg, crushed shells, internal egg contents and sous-vide water were enumerated over time by culturing onto XLD agar. The quality of the uncontaminated heat-treated eggs was determined by measuring the Haugh unit, yolk index, albumen pH, thermocoagulation, and stability of foam. A blind control study was conducted to assess the acceptability and usability of the treated eggs by chefs and food handlers for the preparation of mayonnaise. Complete decontamination of ST was achieved by treating eggs for 9 min in the sous-vide cooker (57°C). No statistically significant difference was observed in the quality of treated eggs compared with nontreated eggs using the quality measurements and acceptability score from chefs. This method provides a simple approach that can be adopted by chefs and food handlers to obtain safe eggs before the preparation of raw egg products.

Climate Change Impacts on Waterborne Diseases: Moving Toward Designing Interventions

PURPOSE

Climate change threatens progress achieved in global reductions of infectious disease rates over recent decades. This review summarizes literature on potential impacts of climate change on waterborne diseases, organized around a framework of questions that can be addressed depending on available data.

RECENT FINDINGS

A growing body of evidence suggests that climate change may alter the incidence of waterborne diseases, and diarrheal diseases in particular. Much of the existing work examines historical relationships between weather and diarrhea incidence, with a limited number of studies projecting future disease rates. Some studies take social and ecological factors into account in considerations of historical relationships, but few have done so in projecting future conditions. The field is at a point of transition, toward incorporating social and ecological factors into understanding the relationships between climatic factors and diarrheal diseases and using this information for future projections. The integration of these components helps identify vulnerable populations and prioritize adaptation strategies.