21 research outputs found
Climate and Landscape Factors Associated with Buruli Ulcer Incidence in Victoria, Australia
Background
Buruli ulcer (BU), caused by Mycobacterium ulcerans (M. ulcerans), is a necrotizing skin disease found in more than 30 countries worldwide. BU incidence is highest in West Africa; however, cases have substantially increased in coastal regions of southern Australia over the past 30 years. Although the mode of transmission remains uncertain, the spatial pattern of BU emergence in recent years seems to suggest that there is an environmental niche for M. ulcerans and BU prevalence.
Methodology/Principal Findings
Network analysis was applied to BU cases in Victoria, Australia, from 1981–2008. Results revealed a non-random spatio-temporal pattern at the regional scale as well as a stable and efficient BU disease network, indicating that deterministic factors influence the occurrence of this disease. Monthly BU incidence reported by locality was analyzed with landscape and climate data using a multilevel Poisson regression approach. The results suggest the highest BU risk areas occur at low elevations with forested land cover, similar to previous studies of BU risk in West Africa. Additionally, climate conditions as far as 1.5 years in advance appear to impact disease incidence. Warmer and wetter conditions 18–19 months prior to case emergence, followed by a dry period approximately 5 months prior to case emergence seem to favor the occurrence of BU.
Conclusions/Significance
The BU network structure in Victoria, Australia, suggests external environmental factors favor M. ulcerans transmission and, therefore, BU incidence. A unique combination of environmental conditions, including land cover type, temperature and a wet-dry sequence, may produce habitat characteristics that support M. ulcerans transmission and BU prevalence. These findings imply that future BU research efforts on transmission mechanisms should focus on potential vectors/reservoirs found in those environmental niches. Further, this study is the first to quantitatively estimate environmental lag times associated with BU outbreaks, providing insights for future transmission investigations.This project was supported by the World Health Organization and the National Institutes of Health and Fogarty International Center (NIH - R01TW007550). The content is solely the responsibility of the authors and does not necessarily represent the official views of the Fogarty International Center or the National Institutes of Health. R.W. Merritt is gratefully acknowledged for supporting this research as part of NIH grant R01TW007550
Recommended from our members
The Go-GN Open Research Handbook
This Handbook draws together work done between 2020 and 2023 by members of the Global OER Graduate Network (GO-GN). GO-GN is a network of PhD candidates around the world whose research projects include a focus on open education. GO-GN is currently funded through the OER programme of The William and Flora Hewlett Foundation and administered by the Open Education Research Hub from the Institute of Educational Technology at The Open University, UK.
In our current phase of activity, we began these collaborative writing efforts with a Research Methods Handbook which was created during the depths of the Covid-19 pandemic. Working together at distance provided an important way to strengthen community links when meeting in person was not possible. The Research Methods Handbook was well received by a much larger audience than we anticipated, and went on to win an Open Research Award. We followed this up with a sister publication, our Conceptual Frameworks Guide. This explores a less well traversed (but nonetheless important) area of scholarly focus. Together, these two explore open approaches to the theory and practice of research in open education. One distinctive feature of our presentation is to foreground the authentic experiences of doctoral researchers who have used specific approaches in researching open education. While it is not possible to cover all approaches in this detail, we hope that important insights are presented in this form of open practice.
Throughout 2020-2022 we also regularly engaged our membership through collective reviews of recently published papers and articles. The Research Reviews serve as an overview of recent research but also as a snapshot of the critical responses recorded by doctoral and post-doctoral researchers working in relevant areas.
No one volume can claim to comprehensively contain the diversity and variety of open approaches, and this is no exception. But one virtue of openness is that we can draw on the openly licensed works of others to increase our coverage of relevant areas. The Additional Resources at the end of this volume bring together a range of openly licensed texts on open education research and suggests places for further reading and research.
Consequently, the information contained here represents a wide range of contributors and collaborators. The original and intended audience for this volume is the doctoral student working on an open education research project - in short, the typical student member of GO-GN and the profile the network exists to support.
However, we’ve learned through feedback and analytics that the potential audience for works like this is much larger. Many people who wouldn’t describe themselves as researchers still do research and evaluation. Presenting accessible insights into research foundations and practices helps with this and can be understood as a form of open practice
Is Predominant Clonal Evolution a Common Evolutionary Adaptation to Parasitism in Pathogenic Parasitic Protozoa, Fungi, Bacteria, and Viruses?
We propose that predominant clonal evolution (PCE) in microbial pathogens be defined as restrained recombination on an evolutionary scale, with genetic exchange scarce enough to not break the prevalent pattern of clonal population structure. The main features of PCE are (1) strong linkage disequilibrium, (2) the widespread occurrence of stable genetic clusters blurred by occasional bouts of genetic exchange ('near-clades'), (3) the existence of a "clonality threshold", beyond which recombination is efficiently countered by PCE, and near-clades irreversibly diverge. We hypothesize that the PCE features are not mainly due to natural selection but also chiefly originate from in-built genetic properties of pathogens. We show that the PCE model obtains even in microbes that have been considered as 'highly recombining', such as Neisseria meningitidis, and that some clonality features are observed even in Plasmodium, which has been long described as panmictic. Lastly, we provide evidence that PCE features are also observed in viruses, taking into account their extremely fast genetic turnover. The PCE model provides a convenient population genetic framework for any kind of micropathogen. It makes it possible to describe convenient units of analysis (clones and near-clades) for all applied studies. Due to PCE features, these units of analysis are stable in space and time, and clearly delimited. The PCE model opens up the possibility of revisiting the problem of species definition in these organisms. We hypothesize that PCE constitutes a major evolutionary strategy for protozoa, fungi, bacteria, and viruses to adapt to parasitism
Recommended from our members
Open Rangers in Ontario: Fostering Open Community
Jenni Hayman, Program Manager for eCampusOntario will provide insight into new strategies that may help launch and sustain higher education open working groups. Using the Ontario Open Rangers as an example, Jenni will describe her work with this new community of practice, and share the Open Ranger Toolkit.
In this brief session I will cover the basics of the eCampusOntario Open Rangers initiative and describe some of the strategies for community building for higher education open working groups. Elements of the Open Ranger Toolkit will be shared and participants will be invited to describe challenges and successes starting or sustaining open working groups on their own campuses. The ed tech tool Padlet will be used (a collaborative digital whiteboard) to capture participant input and reflection, all materials will be linked and shared
Buruli ulcer incidence in Australia from 1939–2008.
<p>The value for each state represents the percentage of total reported Buruli ulcer cases for Australia during this time period.</p
Statistical modeling flowchart.
<p>The flowchart shows the multiple stages of model development and variable selection. Variable definitions: “For” = Proportion of Forest, “Urb” = Proportion of Urban, “Min E” = Minimum Elevation, “Mean E” = Mean Elevation, “TP” = Total Precipitation, “SDP” = Standard Deviation of Precipitation, “Mx” = Maximum Temperatures, and “Mn” = Minimum Temperatures. For the climate variables, the notation “T – [number]” refers to the given <i>variable</i> at the specified <i>number</i> of months prior to BU case incidence.</p
The “actual” Victoria BU disease network from 1981–2008.
<p>The centroids of each locality represent the nodes of the network (the black triangles) and the links between consecutive BU cases are represented by lines connecting the nodes.</p