Infectious Diseases Attributable to Non-optimal Temperature in Australia: Current Burden and Future Projections in a Changing Climate
Background: Climate change poses significant risks for emerging and re-emerging of infectious diseases. While studies have documented the association between non-optimal temperature and infectious disease transmission, evidence for the temperature-attributable burden of these diseases using comprehensive measures like Disability-Adjusted Life Years (DALYs) remains limited. This study aimed to quantify the current and future national and sub-national temperature-attributable burden of Ross River virus (RRV), Salmonella, and Campylobacter infections in Australia. Methodology: The method utilised in this thesis followed the Comparative Risk Assessment framework, aligned with the Global Burden of Disease and the Australian Institute of Health and Welfare (AIHW)’s Australian Burden of Disease methodologies. Data on DALYs due to RRV, Salmonella, and Campylobacter infections for 2003–2018 were obtained from AIHW. The temperature-attributable burden was estimated using a three-step process: First, systematic reviews and meta-analyses determined the relative risk (RR) per 1°C increase in temperature for the selected diseases. Next, these RRs were adjusted to the Australian context using a multivariate meta-regression model to obtain location-specific RRs for each Statistical Area Level 2 (suburbs), which, combined with gridded temperature data, derived the population attributable fractions (PAFs). Finally, the PAFs were applied to the annual average DALYs to estimate the temperature-attributable burden. Future projections for the 2030s and 2050s were made using downscaled climate models under two greenhouse gas emissions scenarios (RCP4.5 and RCP8.5), considering demographic changes and human adaptation to climate change. Results: During the baseline period (2003-2018), increasing non-optimal temperatures accounted for 19.1% (35.8 YLD), 11.2% (41.8 DALYs), and 8.5% (28.1 DALYs) of the observed burden for RRV, Salmonella, and Campylobacter infections in Australia, respectively. The impact of temperature on disease burden varied by region, with the Northern Territory (NT) having the highest burden (26.3%, 13.6%, and 11.7% for RRV, Salmonella, and Campylobacter infections), followed by Queensland (QLD: 21%, 13.4% and 9.7%). Both NT and QLD had burdens at least double the national average. Projections indicated that without adaptation, the burden of these three temperature-attributable infectious diseases in Australia could be more than double by the 2050s compared to the baseline period, assuming medium population growth. Implications of findings: Increasing temperatures will likely increase the risk of infectious diseases burden in Australia in a warming climate. Findings highlight the importance of accounting for regional climate conditions, population characteristics, and disease subgroups when assessing temperature-related infectious disease risks. This national and sub-national assessment of disease burden attributable to temperature exposure improves understanding of health impacts and highlights the need for region-specific adaptation strategies to mitigate future infectious disease burden in the context of climate change. Conclusion: This research provided a nationwide analysis of the current and projected burden of infectious diseases (RRV, Salmonella, and Campylobacter) associated with increasing mean temperatures in Australia, using DALYs as a comprehensive measure of disease burden. The findings showed that rising temperatures increase the burden of infectious diseases, with varying effects across regions, underscoring the need for location-specific adaptation and mitigation strategies to minimize the adverse health consequences of climate change on infectious disease transmission.
Adaptation, Attributable burden, Burden of disease Campylobacter infection, Climate change, Climate zone, Infectious diseases, Non-optimal temperature Projection, Relative Risk, Rising temperature, Ross River virus infection, Salmonella infection
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