Spatial Modelling tools to integrate public health and environmental science, illustrated with infectious cryptosporidiosis

Contemporary spatial modelling tools can help examine how environmental exposures such as climate and land use together with socio-economic factors sustain infectious disease transmission in humans. Spatial methods can account for interactions across global and local scales, geographic clustering and continuity of the exposure surface, key characteristics of many environmental influences. Using cryptosporidiosis as an example, this review illustrates how, in resource rich settings, spatial tools have been used to inform targeted intervention strategies and forecast future disease risk with scenarios of environmental change. When used in conjunction with molecular studies, they have helped determine location-specific infection sources and environmental transmission pathways. There is considerable scope for such methods to be used to identify data/infrastructure gaps and establish a baseline of disease burden in resource-limited settings. Spatial methods can help integrate public health and environmental science by identifying the linkages between the physical and socio-economic environment and health outcomes. Understanding the environmental and social context for disease spread is important for assessing the public health implications of projected environmental change

The Risk of Reported Cryptosporidiosis in Children Aged < 5 Years in Australia is Highest in Very Remote Regions

The incidence of cryptosporidiosis is highest in children <5 years, yet little is known about disease patterns across urban and rural areas of Australia. In this study, we examine whether the risk of reported cryptosporidiosis in children <5 years varies across an urban-rural gradient, after controlling for season and gender. Using Australian data on reported cryptosporidiosis from 2001 to 2012, we spatially linked disease data to an index of geographic remoteness to examine the geographic variation in cryptosporidiosis risk using negative binomial regression. The Incidence Risk Ratio (IRR) of reported cryptosporidiosis was higher in inner regional (IRR 1.4 95% CI 1.2-1.7, p < 0.001), and outer regional areas (IRR 2.4 95% CI 2.2-2.9, p < 0.001), and in remote (IRR 5.2 95% CI 4.3-6.2, p < 0.001) and very remote (IRR 8.2 95% CI 6.9-9.8, p < 0.001) areas, compared to major cities. A linear test for trend showed a statistically significant trend with increasing remoteness. Remote communities need to be a priority for future targeted health promotion and disease prevention interventions to reduce cryptosporidiosis in children <5 years

Establishing thresholds and parameters for pandemic influenza severity assessment, Australia

Objective: To implement the World Health Organization's pandemic influenza severity assessment tool in Australia, using multiple sources of data to establish thresholds and measure influenza severity indicators. Methods: We used data from four reliable sources: sentinel general practitioner surveillance, hospital surveillance, a public health hotline and an influenza-like illness survey system. We measured three influenza severity indicators (transmissibility, impact and disease seriousness) defined using pandemic influenza severity assessment guidelines. We used the moving epidemic method and a seriousness indicator-specific method to set thresholds for indicator parameters using 2012-2016 data. We then applied the thresholds to data from the 2017 influenza season. Findings: We were able to measure and produce thresholds for each severity indicator. At least one laboratory-confirmed influenza parameter was used to measure each indicator. When thresholds were applied to the 2017 season, there was good agreement across all data sources in measuring activity for each indicator. The season was characterized as having high transmissibility and extraordinary impact. Seriousness was characterized as moderate overall and in all age groups except those aged ≥ 65 years for whom it was high. This matched the description of the season produced by the Australian national influenza surveillance committee, based on expert opinion and historical ranges. Conclusion: The pandemic influenza severity assessment and moving epidemic method provide a robust and flexible method to enable an evidence-based assessment of seasonal influenza severity across diverse data sources. This is useful for national assessment and will contribute to global monitoring and response to circulating influenza with pandemic potential.Flutracking, the influenza complications alert network and the Australian sentinel practices research network are supported by the Australian Department of Health. Healthdirect Australia is supported by the Australian and state and territory governments. This research was supported by scholarship funding for the Master of Philosophy (Applied Epidemiology) at the Australian National Universit

An epidemiologic approach to environmental monitoring: cyanobacteria in Australia's Murray-Darling basin

Risk based management of aquatic resources for ecosystem and public health requires water managers and health professionals to work together. Using an epidemiologic time-series modelling approach, we assess patterns of risk for alert-level cyanobacterial abundance with water temperature. We focus on six sites along the Murray-Darling Drainage Basin, using the longest continuous record of algal abundance in Australia. Alert-level cyanobacterial abundance showed a non-linear and lagged response to water temperature across all six sites, after controlling for relative water discharge. For three sites there was a positive relationship of high-water temperature with the risk of alert-level abundance. These three sites also showed a substantial lagged effect, with the risk remaining high at a lag of 1 month following high water temperatures. The higher than average risk of alert-level cyanobacterial abundance with extreme water temperature and the persistence of this effect for 1 month highlight the applicability of these models to understand non-linear and time-dependent relationships in complex systems which are managed for ecosystem and population health. The site-specific relationships provide guidance for local authorities to develop water quality-related environmental and public health responses to a variable climate

Water access as a required public health intervention to fight COVID-19 in the Pacific Islands

In 2015, 193 United Nations (UN) member countries adopted Agenda 2030 as an agreed framework for sustainable development to 2030 [1], with seventeen sustainable development goals (SDGs). For health, water and sanitation, the relevant goals are SDG 3, to "ensure healthy lives and promote well-being for all at all ages", and SDG 6, to "ensure availability and sustainable management of water and sanitation for all"

A Spatially-explicit Microsimulation Analysis of a Proposed Sugar Tax in the Australian Capital Territory

This study aimed to estimate the spatially explicit impact of a 20% proposed tax on sugar sweetened beverage (SSB) consumption across small areas within the Australian Capital Territory (ACT). The study is important in the context of informing ongoing debate around a proposal to introduce a 20% tax on the sugar content of SSBs. A microsimulation analysis was used to estimate current expenditure on SSBs and the impact of a tax at a small area level across the ACT. Population data from the Census was used to weight survey data from the Household Expenditure Survey. A microsimulation model was then applied to the data to estimate current expenditure on SSBs, and the tax impact of a 20% sugar tax on SSBs. The impact of a sugar tax falls unequally across regions of the ACT with the tax impact representing a higher proportion of income for areas with lower socioeconomic advantage. The current expenditure ($/household/annum) averaged around$300 and the tax impact of the proposed sugar tax as a percentage of income averaged around 0.12%/household/ annum. The unequal distribution of tax impact estimated by the model suggests that coupling the tax with targeted exercise and nutrition programs as well as systemic change will both be required to reduce inequalities and increase the likelihood of positive health outcomes around overweight and obesity and related conditions.This research was funded by an Australian National University Research School of Social Sciences Cross-College gran

A Bayesian spatio-temporal framework to identify outbreaks and examine environmental and social risk factors for infectious diseases monitored by routine surveillance

Spatio-temporal disease patterns can provide clues to etiological pathways, but can be complex to model. Using a flexible Bayesian hierarchical framework, we identify previously undetected space-time clusters and environmental and socio-demographic risk factors for reported giardiasis and cryptosporidiosis at the New Zealand small area level. For giardiasis, there was no seasonal pattern in outbreak probability and an inverse association with density of dairy cattle (β^₁= -0.09, Incidence Risk Ratio (IRR) 0.90 (95% CI 0.84, 0.97) per 1 log increase in cattle/km²). In dairy farming areas, cryptosporidiosis outbreaks were observed in spring. Reported cryptosporidiosis was positively associated with dairy cattle density: β^₁= 0.12, IRR 1.13 (95% CI 1.05, 1.21) per 1 log increase in cattle/km2 and inversely associated with weekly average temperature: β^₁=-0.07, IRR 0.92 (95% CI 0.87, 0.98) per 4°C increase. This framework can be generalized to determine the potential drivers of sporadic cases and latent outbreaks of infectious diseases of public health importance

An assessment of climate change and health vulnerability and adaptation in dominica

A climate change and health vulnerability and adaptation assessment was conducted in Dominica, a Caribbean small island developing state located in the Lesser Antilles. The assessment revealed that the country’s population is already experiencing many impacts on health and health systems from climate variability and change. Infectious diseases as well as food and waterborne diseases pose continued threats as climate change may exacerbate the related health risks. Threats to food security were also identified, with particular concern for food production systems. The findings of the assessment included near-term and long-term adaptation options that can inform actions of health sector decision-makers in addressing health vulnerabilities and building resilience to climate change. Key challenges include the need for enhanced financial and human resources to build awareness of key health risks and increase adaptive capacity. Other small island developing states interested in pursuing a vulnerability and adaptation assessment may find this assessment approach, key findings, analysis, and lessons learned usefulThis research was funded by Health Canad

Solastalgia mediates between bushfire impact and mental health outcomes: A study of Australia\u27s 2019–2020 bushfire season

In 2019–2020, Australia experienced an unprecedented bushfire season that caused widespread environmental destruction across the continent, and especially to its south-east corner. Over two studies, we examine mental health outcomes of individuals impacted by bushfire, drawing on the concept of solastalgia – the sense of distress arising from unwanted environmental change – as a potential explanation for the mental health consequences of bushfire. In Study 1, we surveyed 2084 residents from the Australian Capital Territory and surrounding regions directly after the bushfire season. Participants were asked about exposure to the 2019–2020 bushfires, and to a previous regional fire of significance, experience of solastalgia, and five mental health indicators. In Study 2, we broaden our focus to all of Australia, and administer our measures with a nationally representative sample six months after the conclusion of the bushfire season (N = 1477). In both studies, we find the severity of reported bushfire impact is significantly associated with mental health, such that greater impact predicts poorer outcomes. Moreover, we find the experience of solastalgia mediates the relationship between bushfire impact and mental health and wellbeing. Experiencing solastalgia is a partial, but important, mechanism for understanding the impact of bushfire exposure on mental health and wellbeing. Importantly, people not directly impacted by a bushfire event also experience solastalgia and subsequent poorer mental health outcomes following bushfires. We suggest that future measurements of the impact of abrupt environmental change events, including bushfires, consider the role of solastalgia and localised environmental contexts in shaping the mental health impacts to the population