News Feature: Climate change hastens disease spread across the globe

The Impacts of Climate Change on the Emergence and Reemergence of Mosquito-Borne Diseases in Temperate Zones: An Umbrella Review Protocol

INTRODUCTION

Mosquito-borne diseases represent a global public health concern and are responsible for over 700 000 deaths globally every year. Additionally, many mosquito species have undergone a dramatic global expansion due to various factors, including climate change, and forecasts indicate that mosquito populations will persist in dispersing beyond their present geographic range, namely in temperate climates. The research literature on this topic has grown in recent years, including some systematic evidence synthesis. However, to provide a comprehensive overview of this growing literature needed for policy action, a summary of this evidence, including existing systematic reviews, is required. This study aims to undertake an umbrella review that explores the impacts of climate change on the emergence and reemergence of diseases transmitted by mosquitoes in temperate zones and the publication of the protocol is a fundamental step to ensure the credibility, transparency and reproducibility of this research.

METHODS AND ANALYSIS

Studies published in scientific journals indexed by PubMed, EMBASE, Cochrane Library, Epistemonikos, and Web of Science Core Collection to be included in this umbrella review will meet the following criteria: the topic of study (climate change and mosquito-borne diseases), regions (temperate zones), study designs (systematic reviews and meta-analysis), language (any) and date (since inception until December 31st, 2023). Titles and abstracts from selected articles will be evaluated by two authors independently and any discrepancy will be resolved through consensus or, if not possible, through a third author. The data will be extracted, and the risk of bias will be evaluated. The quality of the methodology of the included reviews will be assessed using AMSTAR 2. A narrative synthesis will examine the included systematic reviews. The quality of evidence for all outcomes will be judged using the Grading of Recommendations Assessment, Development and Evaluation working group methodology.

Biophysical and structural study of La Crosse virus endonuclease inhibition for the development of new antiviral options

The large Bunyavirales order includes several families of viruses with a segmented ambisense (-) RNA genome and a cytoplasmic life cycle that starts by synthesizing viral mRNA. The initiation of transcription, which is common to all members, relies on an endonuclease activity that is responsible for cap-snatching. In La Crosse virus, an orthobunyavirus, it has previously been shown that the cap-snatching endonuclease resides in the N-terminal domain of the L protein. Orthobunyaviruses are transmitted by arthropods and cause diseases in cattle. However, California encephalitis virus, La Crosse virus and Jamestown Canyon virus are North American species that can cause encephalitis in humans. No vaccines or antiviral drugs are available. In this study, three known Influenza virus endonuclease inhibitors (DPBA, L-742,001 and baloxavir) were repurposed on the La Crosse virus endonuclease. Their inhibition was evaluated by fluorescence resonance energy transfer and their mode of binding was then assessed by differential scanning fluorimetry and microscale thermophoresis. Finally, two crystallographic structures were obtained in complex with L-742,001 and baloxavir, providing access to the structural determinants of inhibition and offering key information for the further development of Bunyavirales endonuclease inhibitors.

Mimicking an in cellulo environment for enzyme-free paper-based nucleic acid tests at the point of care

Point of care (PoC) nucleic acid amplification tests (NAATs) are a cornerstone of public health, providing the earliest and most accurate diagnostic method for many communicable diseases, such as HIV, in the same location the patient receives treatment. Communicable diseases disproportionately impact low-resource communities where NAATs are often unobtainable due to the resource intensive enzymes that drive the tests. Enzyme-free nucleic acid detection methods, such as hybridization chain reaction (HCR), use DNA secondary structures for self-driven amplification schemes producing large DNA nanostructures and capable of single molecule detection in cellulo. These thermodynamically driven DNA-based tests have struggled to penetrate the PoC diagnostic field due to their inadequate limits of detection or complex workflows. Here we present a proof-of-concept NAAT that combines HCR-based amplification of a target nucleic acid sequence with paper-based nucleic acid filtration and enrichment capable of detecting sub pM levels of synthetic DNA. We reconstruct the favorable hybridization conditions of an in cellulo reaction in vitro by incubating HCR in an evaporating, microvolume environment containing poly(ethylene glycol) as a crowding agent. We demonstrate that the kinetics and thermodynamics of DNA-DNA and DNA-RNA hybridization is enhanced by the dynamic evaporating environment and inclusion of crowding agents, bringing HCR closer to meeting PoC NAAT needs.

Alcohol's contribution to climate change and other environmental degradation: a call for research

Climate change is the single biggest health threat facing humanity. The production, distribution and consumption of many fast-moving consumer goods contribute substantially to climate change, principally through releasing greenhouse gas emissions. Here we consider just some of the ways that alcohol-already a key contributor to an array of health, social and economic burdens-exacerbates environmental harms and climate change. We explore current evidence on alcohol production as a resource- and energy-intensive process, contributing to significant environmental degradation through water usage and other carbon emission costs. We argue that the impacts of alcohol production on climate change have been minimally explored by researchers. Yet the extent of the unfolding catastrophe beholds us to consider all available ways to mitigate unnecessary emissions, including from products such as alcohol. We then turn to suggestions for a research agenda on this topic, including investigations of commercial determinants, inequalities and product advice to help consumers choose lower-carbon options. We conclude by arguing that public health researchers already have an array of methodological expertise and experience that is well placed to produce the evidence needed to inform regulation and efforts by alcohol producers and consumers to minimize their contributions to environmental harms.

Chikungunya virus infection in the southernmost state of Brazil was characterised by self-limited transmission (2017-2019) and a larger 2021 outbreak

BACKGROUND

Chikungunya is a mosquito-borne virus that has been causing large outbreaks in the Americas since 2014. In Brazil, Asian-Caribbean (AC) and East-Central-South-African (ECSA) genotypes have been detected and lead to large outbreaks in several Brazilian states. In Rio Grande do Sul (RS), the southernmost state of Brazil, the first cases were reported in 2016.

OBJECTIVES AND METHODS

We employed genome sequencing and epidemiological investigation to characterise the Chikungunya fever (CHIKF) burden in RS between 2017-2021.

FINDINGS

We detected an increasing CHIKF burden linked to travel associated introductions and communitary transmission of distinct lineages of the ECSA genotype during this period.

MAIN CONCLUSIONS

Until 2020, CHIKV introductions were most travel associated and transmission was limited. Then, in 2021, the largest outbreak occurred in the state associated with the introduction of a new ECSA lineage. CHIKV outbreaks are likely to occur in the near future due to abundant competent vectors and a susceptible population, exposing more than 11 million inhabitants to an increasing infection risk.

Australian young people's perceptions of the commercial determinants of the climate crisis

There is increasing public health focus on how corporate practices impact population health and well-being. While the commercial determinants of the climate crisis pose serious threats to human and planetary health, governments largely seek to balance climate action with economic imperatives. Global stakeholders recognize that young people have important voices in influencing climate responses. However, few studies have investigated young people's perceptions of the commercial determinants of the climate crisis. A qualitatively led online survey of n = 500 young Australians (15-24 years) investigated their understanding of corporate responses to the climate crisis, factors that influenced these responses and strategies to respond. A reflexive approach to thematic analysis was used. Three themes were constructed from the data. First, young people perceived that corporate responses to the climate crisis focussed on soft options and lacked meaningful action. Second, they stated that these responses were largely influenced by economic imperatives rather than planetary health, with policy levers needed to implement environmentally responsible corporate practices. Third, young people perceived that systems needed change to create demand for a cleaner environment, leading to improved practices. Young people have a clear understanding of the commercial determinants of the climate crisis and associated threats to population health. They recognize that corporate practices (and consumer demand) will not change without significant policy and structural change. Public health and health promotion stakeholders should work alongside young people to influence decision-makers to address harmful corporate behaviours.