The climate change-infectious disease nexus: is it time for climate change syndemics?

Effects of ophidiomycosis on movement, survival, and reproduction of eastern foxsnakes (Pantherophis vulpinus)

Ophidiomycosis (snake fungal disease) is caused by the fungal pathogen Ophidiomyces ophidiicola, which causes dermal lesions, occasional systemic infections, and in some cases, mortality. To better understand potential conservation implications of ophidiomycosis (i.e., population-level effects), we investigated its impacts on individual fitness in a population of endangered eastern foxsnakes (Pantherophis vulpinus). We tracked 38 foxsnakes over 6 years and quantified body condition, movement patterns, oviposition rates, and survival. Body condition, distance travelled, and oviposition rates were similar between snakes with and without ophidiomycosis. Interestingly, snakes that tested positive for the pathogen travelled farther, suggesting that movement through a greater diversity of habitats increases risk of exposure. Ophidiomycosis did not negatively affect survival, and most apparently infected snakes persisted in a manner comparable to snakes without ophidiomycosis. Only one mortality was directly attributed to ophidiomycosis, although infected snakes were overrepresented in a sample of snakes killed by predators. Overall, our results suggest that ophidiomycosis may have sublethal effects on eastern foxsnakes, but do not suggest direct effects on survival, ovipositioning, or viability of the study population.

A hot topic at the environment-health nexus: investigating the impact of climate change on infectious diseases

CLIMATE CHANGE - THE ULTIMATE CHALLENGE OF OUR TIME

COVID-19 pandemic aside, climate change is the ultimate challenge of our time. However, to date, there has been insufficient political thrust to make that much-needed climate action a reality.

CLIMATE CHANGE AND INFECTIOUS DISEASES

Infectious diseases represent only one facet of the threats arising from climate change. Direct impacts from climate change include the more frequent occurrence and increased magnitude of extreme weather events, as well as changing temperatures and precipitation patterns. For climate-sensitive infectious diseases, these changes implicate a shift in geographical and temporal distribution, seasonality, and transmission intensity.

SIZING UP THE PROBLEM

Susceptibility to the deleterious effects of climate change is a net result of the interplay of not only environmental factors, but also human, societal, and economic factors, with social inequalities being a major determinant of vulnerability. The global South is already disproportionately affected by the climate crisis. The financial capacity to pursue adaptation options is also limited and unevenly distributed.

CONCLUSIONS

Climate change-induced mortality and morbidity from both infectious and non-infectious diseases, among other adverse scenarios, are expected to rise globally in the future. The coming decade will be crucial for using all remaining opportunities to develop and implement adequate mitigation and adaptation strategies.

Are There Global Syndemics?

In this article, we address the nature of syndemics and whether, as some have asserted, these epidemiological phenomena are global configurations. Our argument that syndemics are not global rests on recognition that they are composed of social/environment contexts, disease clusters, demographics, and biologies that vary across locations. These points are illustrated with the cases of syndemics involving COVID-19, diabetes mellitus, and HIV/AIDS. We draw on theoretical discourse from epidemiology, biology, and anthropology to present what we believe is a more accurate framework for thinking about syndemics with shared elements.

Syndemics: A Cross-Disciplinary Approach to Complex Epidemic Events Like COVID-19

In this review, we trace the origins and dissemination of syndemics, a concept developed within critical medical anthropology that rapidly diffused to other fields. The goal is to provide a review of the literature, with a focus on key debates. After a brief discussion of the nature and significance of syndemic theory and its applications, we trace the history and development of the syndemic framework within anthropology and the contributions of anthropologists who use it. We also look beyond anthropology to the adoption and use of syndemics in other health-related disciplines, including biomedicine, nursing, public health, and psychology, and discuss controversies in syndemics, particularly the perception that existing syndemics research focuses on methodologies at the individual level rather than at the population level and fails to provide evidence of synergistic interactions. Finally, we discuss emerging syndemics research on COVID-19 and provide an overview of the application of syndemics research.

Syndemics and the history of disease: Towards a new engagement

Historians of medicine and disease have yet to think through a syndemic lens. This commentary aims to point out why they should. Although there are several hurdles to overcome, our histories of disease and our understanding of current syndemics both stand to gain should historians begin to explore episodes of cooccurring diseases that share root causes.

Revisiting Ophidiomycosis (Snake Fungal Disease) After a Decade of Targeted Research

Emerging infectious diseases (EIDs) are typically characterized by novelty (recent detection) and by increasing incidence, distribution, and/or pathogenicity. Ophidiomycosis, also called snake fungal disease, is caused by the fungus Ophidiomyces ophidiicola (formerly “ophiodiicola”). Ophidiomycosis has been characterized as an EID and as a potential threat to populations of Nearctic snakes, sparking over a decade of targeted research. However, the severity of this threat is unclear. We reviewed the available literature to quantify incidence and effects of ophidiomycosis in Nearctic snakes, and to evaluate whether the evidence supports the ongoing characterization of ophidiomycosis as an EID. Data from Canada remain scarce, so we supplemented the literature review with surveys for O. ophidiicola in the Canadian Great Lakes region. Peer-reviewed reports of clinical signs consistent with ophidiomycosis in free-ranging, Nearctic snakes date back to at least 1998, and retrospective molecular testing of samples extend the earliest confirmed record to 1986. Diagnostic criteria varied among publications (n = 33), confounding quantitative comparisons. Ophidiomycosis was diagnosed or suspected in 36/121 captive snakes and was fatal in over half of cases (66.7%). This result may implicate captivity-related stress as a risk factor for mortality from ophidiomycosis, but could also reflect reporting bias (i.e., infections are more likely to be detected in captive snakes, and severe cases are more likely to be reported). In contrast, ophidiomycosis was diagnosed or suspected in 441/2,384 free-ranging snakes, with mortality observed in 43 (9.8 %). Ophidiomycosis was only speculatively linked to population declines, and we found no evidence that the prevalence of the pathogen or disease increased over the past decade of targeted research. Supplemental surveys and molecular (qPCR) testing in Ontario, Canada detected O. ophidiicola on 76 of 657 free-ranging snakes sampled across ~136,000 km². The pathogen was detected at most sites despite limited and haphazard sampling. No large-scale mortality was observed. Current evidence supports previous suggestions that the pathogen is a widespread, previously unrecognized endemic, rather than a novel pathogen. Ophidiomycosis may not pose an imminent threat to Nearctic snakes, but further research should investigate potential sublethal effects of ophidiomycosis such as altered reproductive success that could impact population growth, and explore whether shifting environmental conditions may alter host susceptibility.

Food for thought: food systems, livestock futures and animal health

Global food security, livestock production and animal health are inextricably bound. However, our focus on the future tends to disaggregate food and health into largely separate domains. Indeed, much foresight work is either food systems or health-based with little overlap in terms of predictions or narratives. Work on animal health is no exception. Part of the problem is the fundamental misunderstanding of the role, nature and impact of the modern futures tool kit. Here, I outline three key issues in futures research ranging from methodological confusion over the application of scenarios to the failure to effectively integrate multiple methodologies to the gap between the need for more evidence and power and control over futures processes. At its core, however, a better understanding of the narrative and worldview framing much of the futures work in animal health is required to enhance the value and impact of such exercises.