ORCID Profile
0000-0001-8463-7858
Current Organisations
Mississippi State University
,
Cornell University
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Publisher: Wiley
Date: 20-01-2022
DOI: 10.1111/CONL.12869
Abstract: Anthropogenic land use change is a major driver of zoonotic pathogen spillover from wildlife to humans. According to the land use‐induced spillover model, land use change alters environmental conditions that in turn alter the dynamics between zoonotic pathogens and their wildlife hosts. Thus, in response to the global spread of the SARS‐CoV‐2 virus (the agent of COVID‐19 disease), there have been renewed calls for landscape conservation as a disease preventive measure, including by the G7 Ministers responsible for Climate and the Environment. Landscape immunity, as a new construct, points to four paradigm shifts the world must favor to effectively mitigate pandemic risks. We provide a landscape immunity primer for policy makers and make the case for “world views” that place Homo sapiens within ecological systems, regard human health as an ecological service, prioritize investments in prevention, and apply ecological restoration to human health goals. Crisis is a conversation starter for reimagining and recommitting ourselves to what is most vital and generative. We urge world leaders to make the move to a nature‐positive world.
Publisher: Springer Science and Business Media LLC
Date: 13-01-2022
Publisher: IUCN
Date: 11-03-2021
Publisher: Public Library of Science (PLoS)
Date: 25-05-2022
DOI: 10.1371/JOURNAL.PONE.0268549
Abstract: The black flying fox ( Pteropus alecto ) is a natural reservoir for Hendra virus, a paramyxovirus that causes fatal infections in humans and horses in Australia. Increased excretion of Hendra virus by flying foxes has been hypothesized to be associated with physiological or energetic stress in the reservoir hosts. The objective of this study was to explore the leukocyte profiles of wild-caught P . alecto , with a focus on describing the morphology of each cell type to facilitate identification for clinical purposes and future virus spillover research. To this end, we have created an atlas of images displaying the commonly observed morphological variations across each cell type. We provide quantitative and morphological information regarding the leukocyte profiles in bats captured at two roost sites located in Redcliffe and Toowoomba, Queensland, Australia, over the course of two years. We examined the morphology of leukocytes, platelets, and erythrocytes of P . alecto using cytochemical staining and characterization of blood films through light microscopy. Leukocyte profiles were broadly consistent with previous studies of P . alecto and other Pteropus species. A small proportion of in idual s les presented evidence of hemoparasitic infection or leukocyte morphological traits that are relevant for future research on bat health, including unique large granular lymphocytes. Considering hematology is done by visual inspection of blood smears, ex les of the varied cell morphologies are included as a visual guide. To the best of our knowledge, this study provides the first qualitative assessment of P . alecto leukocytes, as well as the first set of published hematology reference images for this species.
Publisher: Wiley
Date: 10-11-2014
DOI: 10.1002/ECE3.1315
Publisher: Cold Spring Harbor Laboratory
Date: 08-09-2023
Publisher: Springer Science and Business Media LLC
Date: 27-09-2021
DOI: 10.1186/S12864-021-07994-4
Abstract: Transmissible cancers lie at the intersection of oncology and infectious disease, two traditionally ergent fields for which gene expression studies are particularly useful for identifying the molecular basis of phenotypic variation. In oncology, transcriptomics studies, which characterize the expression of thousands of genes, have identified processes leading to heterogeneity in cancer phenotypes and in idual prognoses. More generally, transcriptomics studies of infectious diseases characterize interactions between host, pathogen, and environment to better predict population-level outcomes. Tasmanian devils have been impacted dramatically by a transmissible cancer (devil facial tumor disease DFTD) that has led to widespread population declines. Despite initial predictions of extinction, populations have persisted at low levels, due in part to heterogeneity in host responses, particularly between sexes. However, the processes underlying this variation remain unknown. We sequenced transcriptomes from healthy and DFTD-infected devils, as well as DFTD tumors, to characterize host responses to DFTD infection, identify differing host-tumor molecular interactions between sexes, and investigate the extent to which tumor gene expression varies among host populations. We found minimal variation in gene expression of devil lip tissues, either with respect to DFTD infection status or sex. However, 4088 genes were differentially expressed in tumors among our s ling localities. Pathways that were up- or downregulated in DFTD tumors relative to normal tissues exhibited the same patterns of expression with greater intensity in tumors from localities that experienced DFTD for longer. No mRNA sequence variants were associated with expression variation. Expression variation among localities may reflect morphological differences in tumors that alter ratios of normal-to-tumor cells within biopsies. Phenotypic variation in tumors may arise from environmental variation or differences in host immune response that were undetectable in lip biopsies, potentially reflecting variation in host-tumor coevolutionary relationships among sites that differ in the time since DFTD arrival.
Publisher: Cold Spring Harbor Laboratory
Date: 08-03-2021
DOI: 10.1101/2021.03.04.21252949
Abstract: SARS-CoV-2 spreads quickly in dense populations, with serious implications for universities, workplaces, and other settings where exposure reduction practices are difficult to implement. Rapid screening has been proposed as a tool to slow the spread of the virus however, many commonly used diagnostic tests (e.g., RT-qPCR) are expensive, difficult to deploy (e.g., require a nasopharyngeal specimen), and have extended turn-around times. We evaluated testing regimes that combined diagnostic testing using qPCR with high-frequency screening using a novel reverse-transcription loop-mediated isothermal lification (RT-LAMP, herein LAMP) assay. We used a compartmental susceptible-exposed-infectious-recovered (SEIR) model to simulate screening of a university population. We also developed a Shiny application to allow administrators and public health professionals to develop optimal testing strategies given site-specific assumptions about testing investment, target population, and cost. The frequency of screening, especially when pooling s les, was more important for minimizing epidemic size than test sensitivity, behavioral compliance, contact tracing capacity, and time between testing and results. Our results suggest that when testing budgets are limited, it is safer and more cost-effective to allocate the majority of funds to screening. Rapid, cost-effective, and scalable screening tests, like LAMP, should be viewed as critical components of SARS-CoV-2 testing in high-density populations.
Publisher: Springer Science and Business Media LLC
Date: 19-11-2021
Publisher: Frontiers Media SA
Date: 29-03-2022
DOI: 10.3389/FIMMU.2022.858423
Abstract: The identification of practical early diagnostic biomarkers is a cornerstone of improved prevention and treatment of cancers. Such a case is devil facial tumor disease (DFTD), a highly lethal transmissible cancer afflicting virtually an entire species, the Tasmanian devil ( Sarcophilus harrisii ). Despite a latent period that can exceed one year, to date DFTD diagnosis requires visual identification of tumor lesions. To enable earlier diagnosis, which is essential for the implementation of effective conservation strategies, we analyzed the extracellular vesicle (EV) proteome of 87 Tasmanian devil serum s les using data-independent acquisition mass spectrometry approaches. The antimicrobial peptide cathelicidin-3 (CATH3), released by innate immune cells, was enriched in serum EV s les of both devils with clinical DFTD (87.9% sensitivity and 94.1% specificity) and devils with latent infection (i.e., collected while overtly healthy, but 3-6 months before subsequent DFTD diagnosis 93.8% sensitivity and 94.1% specificity). Although high expression of antimicrobial peptides has been mostly related to inflammatory diseases, our results suggest that they can be also used as accurate cancer biomarkers, suggesting a mechanistic role in tumorous processes. This EV-based approach to biomarker discovery is directly applicable to improving understanding and diagnosis of a broad range of diseases in other species, and these findings directly enhance the capacity of conservation strategies to ensure the viability of the imperiled Tasmanian devil population.
Publisher: Wiley
Date: 06-2021
DOI: 10.1002/ECE3.7636
Abstract: Devil facial tumor disease (DFTD) is a transmissible cancer affecting Tasmanian devils Sarcophilus harrisii . The disease has caused severe population declines and is associated with demographic and behavioral changes, including earlier breeding, younger age structures, and reduced dispersal and social interactions. Devils are generally solitary, but social encounters are commonplace when feeding upon large carcasses. DFTD tumors can disfigure the jaw and mouth and so diseased in iduals might alter their diets to enable ingestion of alternative foods, to avoid conspecific interactions, or to reduce competition. Using stable isotope analysis (δ 13 C and δ 15 N) of whiskers, we tested whether DFTD progression, measured as tumor volume, affected the isotope ratios and isotopic niches of 94 infected Tasmanian devils from six sites in Tasmania, comprising four eucalypt plantations, an area of smallholdings and a national park. Then, using tissue from 10 devils s led before and after detection of tumors and 8 devils where no tumors were detected, we examined whether mean and standard deviation of δ 13 C and δ 15 N of the same in iduals changed between healthy and diseased states. δ 13 C and δ 15 N values were generally not related to tumor volume in infected devils, though at one site, Freycinet National Park, δ 15 N values increased significantly as tumor volume increased. Infection with DFTD was not associated with significant changes in the mean or standard deviation of δ 13 C and δ 15 N values in in idual devils s led before and after detection of tumors. Our analysis suggests that devils tend to maintain their isotopic niche in the face of DFTD infection and progression, except where ecological conditions facilitate a shift in diets and feeding behaviors, demonstrating that ecological context, alongside disease severity, can modulate the behavioral responses of Tasmanian devils to DFTD.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-12-2020
Abstract: The emergence of a devastating transmissible facial cancer among Tasmanian devils over the past few decades has caused substantial concern for their future because these animals are already threatened by a regional distribution and other stressors. Little is known about the overall history and trajectory of this disease. Patton et al. used an epidemiological phylodynamic approach to reveal the pattern of disease emergence and spread. They found that low Tasmanian devil densities appear to be contributing to slower disease growth and spread, which is good news for Tasmanian devil persistence and suggests that care should be taken when considering options for increasing devil populations. Science , this issue p. eabb9772
Publisher: Wiley
Date: 14-09-2021
DOI: 10.1002/ECE3.8107
Abstract: The COVID‐19 pandemic has highlighted the importance of efficient s ling strategies and statistical methods for monitoring infection prevalence, both in humans and in reservoir hosts. Pooled testing can be an efficient tool for learning pathogen prevalence in a population. Typically, pooled testing requires a second‐phase retesting procedure to identify infected in iduals, but when the goal is solely to learn prevalence in a population, such as a reservoir host, there are more efficient methods for allocating the second‐phase s les. To estimate pathogen prevalence in a population, this manuscript presents an approach for data fusion with two‐phased testing of pooled s les that allows more efficient estimation of prevalence with less s les than traditional methods. The first phase uses pooled s les to estimate the population prevalence and inform efficient strategies for the second phase. To combine information from both phases, we introduce a Bayesian data fusion procedure that combines pooled s les with in idual s les for joint inferences about the population prevalence. Data fusion procedures result in more efficient estimation of prevalence than traditional procedures that only use in idual s les or a single phase of pooled s ling. The manuscript presents guidance on implementing the first‐phase and second‐phase s ling plans using data fusion. Such methods can be used to assess the risk of pathogen spillover from reservoir hosts to humans, or to track pathogens such as SARS‐CoV‐2 in populations.
Publisher: Wildlife Disease Association
Date: 07-2011
DOI: 10.7589/0090-3558-47.3.734
Abstract: Ruminants are the principal host for infection by Mycobacterium avium subsp. paratuberculosis (Map), the cause of Johne's disease. Based on studies of a Map-infected population of European rabbits (Oryctolagus cuniculus) in Scotland, lagomorphs as a broad taxonomic order were proposed as potential nonruminant reservoirs for Map. To determine whether a different lagomorph species may serve as a wildlife reservoir, we investigated Map infection in European hares (Lepus europaeus) sharing habitat with known Map-infected dairy cattle in southern Chile. Fecal, mesenteric lymph node, and ileal s les were aseptically collected from 385 wild hares for liquid culture and real-time polymerase chain reaction identification of acid-fast isolates. All tissue s les were also acid-fast stained and examined microscopically. We isolated Map from at least one tissue from 48 hares (12.6%) and fecal s les from 16 hares (4.2%). No Map was found in tissues of eight of the fecal-culture-positive hares. Histologically, all tissues from all hares were within normal limits, and no acid-fast organisms were observed in any s le. Active infection, implying lification of the organism secondary to resultant disease, was not evident. With this report Map isolations on a population versus incidental detection have now been made from two lagomorph species. However, although the rabbit population studied in Scotland appears to function as a Map reservoir, the hares studied in Chile appear to be a dead-end host, serving only as potential mechanical vectors for the organism.
Publisher: Oxford University Press (OUP)
Date: 13-10-2018
DOI: 10.1093/GBE/EVY229
Publisher: Oxford University Press (OUP)
Date: 08-2020
DOI: 10.1534/GENETICS.120.303428
Abstract: Spontaneous cancer regression in humans is uncommon, but understanding the mechanisms is key for advancing treatment. Using Devil Facial Tumor Disease as a model, Margres et al. employed comparative....
Publisher: The Royal Society
Date: 21-11-2018
Abstract: Knowledge of the ecological dynamics between hosts and pathogens during the initial stages of disease emergence is crucial to understanding the potential for evolution of new interspecific interactions. Tasmanian devil ( Sarcophilus harrisii ) populations have declined precipitously owing to infection by a transmissible cancer (devil facial tumour disease, DFTD) that emerged approximately 20 years ago. Since the emergence of DFTD, and as the disease spreads across Tasmania, the number of devils has dropped up to 90% across 80% of the species's distributional range. As a result, the disease is expected to act as a strong selective force on hosts to develop mechanisms of tolerance and/or resistance to the infection. We assessed the ability of infected devils to cope with infection, which translates into host tolerance to the cancer, by using the reaction norm of the in idual body condition by tumour burden. We found that body condition of infected hosts is negatively affected by cancer progression. Males and females presented significant differences in their tolerance levels to infection, with males suffering declines of up to 25% of their body condition, in contrast to less than 5% in females. Sex-related differences in tolerance to cancer progression may select for changes in life-history strategies of the host and could also alter the selective environment for the tumours.
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/ZO20046
Abstract: Australia’s 81 bat species play vital ecological and economic roles via suppression of insect pests and maintenance of native forests through pollination and seed dispersal. Bats also host a wide ersity of coronaviruses globally, including several viral species that are closely related to SARS-CoV-2 and other emergent human respiratory coronaviruses. Although there are hundreds of studies of bat coronaviruses globally, there are only three studies of bat coronaviruses in Australian bat species, and no systematic studies of drivers of shedding. These limited studies have identified two betacoronaviruses and seven alphacoronaviruses, but less than half of Australian species are included in these studies and further research is therefore needed. There is no current evidence of spillover of coronaviruses from bats to humans in Australia, either directly or indirectly via intermediate hosts. The limited available data are inadequate to determine whether this lack of evidence indicates that spillover does not occur or occurs but is undetected. Conversely, multiple international agencies have flagged the potential transmission of human coronaviruses (including SARS CoV-2) from humans to bats, and the consequent threat to bat conservation and human health. Australia has a long history of bat research across a broad range of ecological and associated disciplines, as well as expertise in viral spillover from bats. This strong foundation is an ideal platform for developing integrative approaches to understanding bat health and sustainable protection of human health.
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.JPSYCHIRES.2022.01.016
Abstract: Suicide results from complex interactions between biological, psychological, and socioeconomic factors. At the population level, the study of suicide rates and their environmental and social determinants allows us to disentangle some of these complexities and provides support for policy design and preventive actions. In this study we aim to evaluate the associations between environmental and socioeconomic factors and demographically stratified suicide rates on large temporal and spatial scales. Our dataset contains information about yearly suicides rates by sex and age from 2000 through 2017 along a 4000 km latitudinal gradient. We used zero-inflated negative binomial models to evaluate the spatio-temporal influence of each environmental and socioeconomic variable on suicide rates at each sex/age combination. Overall, we found differential patterns of associations between suicide rates and explanatory variables by age and sex. Suicide rates in men increases in middle and high latitude regions and intermediate age classes. For adolescent and adult women, we found a similar pattern with an increase in suicide rates at middle and high latitudes. Sex differences measured by the male/female suicide ratio shows a marked increase with age. We found that cloudiness has a positive effect on suicide rates in both men and women 24 years old or younger. Regional poverty shows a major impact on men in age classes above 35 years old, an effect that was absent in women. Alcohol and marijuana consumption showed no significant effect sizes. Our findings support high spatio-temporal variability in suicide rates in interaction with extrinsic factors. Several strong differential impacts of environmental and socioeconomic variables on suicide rates depending on sex and age were detected. These results suggest that the design of public policies and interventions to reduce suicide prevalence need to consider the local social and environmental contexts of target populations.
Publisher: Hindawi Limited
Date: 17-08-2022
DOI: 10.1111/TBED.14277
Abstract: Natural herbivore populations have experienced uninterrupted pressures from direct and evident domestic-wildlife interactions and competition, to indirect or less obvious ones such as pathogen transmission. Thus, pathogen spillover between wild and domestic animals is a constant concern because the domestic-wildlife interface represents the ecological frontier in which pathogen transmission takes place in both directions. In Patagonian steppe communities, extensive sheep ranching and guanaco (Lama guanicoe) populations coexist, and guanaco have shown to be infected by pathogens such as Mycobacterium avium subspecies paratuberculosis (MAP) likely transmitted from livestock. MAP causes chronic enteritis and affects mostly domestic ruminants. We evaluated MAP prevalence and pathogen shedding in both species' faeces collected in non-shared and shared sites according to presence/absence of sheep and guanaco along a year, in four different seasons (autumn, winter, and spring 2018, and summer 2019). Our results indicate that MAP circulates in both sheep and guanaco populations with self-sustained transmission however, both species differ in their levels of competence. We detected higher pathogen shedding in sites occupied by sheep, suggesting that sheep populations may be the main source of infection for susceptible animals due to their large numbers which drive MAP dynamics.
Publisher: Wiley
Date: 09-10-2018
DOI: 10.1111/EVA.12702
Publisher: MDPI AG
Date: 23-10-2020
Abstract: The impact of emerging infectious diseases is increasingly recognised as a major threat to wildlife. Wild populations of the endangered Tasmanian devil, Sarcophilus harrisii, are experiencing devastating losses from a novel transmissible cancer, devil facial tumour disease (DFTD) however, despite the rapid decline of this species, there is currently no information on the presence of haemoprotozoan parasites. In the present study, 95 Tasmanian devil blood s les were collected from four populations in Tasmania, Australia, which underwent molecular screening to detect four major groups of haemoprotozoa: (i) trypanosomes, (ii) piroplasms, (iii) Hepatozoon, and (iv) haemosporidia. Sequence results revealed Trypanosoma infections in 32/95 in iduals. Trypanosoma copemani was identified in 10 Tasmanian devils from three sites and a second Trypanosoma sp. was identified in 22 in iduals that were grouped within the poorly described T. cyclops clade. A single blood s le was positive for Babesia sp., which most closely matched Babesia lohae. No other blood protozoan parasite DNA was detected. This study provides the first insight into haemoprotozoa from the Tasmanian devil and the first identification of Trypanosoma and Babesia in this carnivorous marsupial.
Publisher: Wiley
Date: 02-08-2020
DOI: 10.1111/MEC.15558
Publisher: Wiley
Date: 07-2020
DOI: 10.1002/ECE3.6513
Publisher: Springer Science and Business Media LLC
Date: 16-10-2021
DOI: 10.1007/S00018-021-03955-Y
Abstract: The iconic Tasmanian devil (Sarcophilus harrisii) is endangered due to the transmissible cancer Devil Facial Tumour Disease (DFTD), of which there are two genetically independent subtypes (DFT1 and DFT2). While DFT1 and DFT2 can be differentially diagnosed using tumour biopsies, there is an urgent need to develop less-invasive biomarkers that can detect DFTD and distinguish between subtypes. Extracellular vesicles (EVs), the nano-sized membrane-enclosed vesicles present in most biofluids, represent a valuable resource for biomarker discovery. Here, we characterized the proteome of EVs from cultured DFTD cells using data-independent acquisition-mass spectrometry and an in-house spectral library of > 1500 proteins. EVs from both DFT1 and DFT2 cell lines expressed higher levels of proteins associated with focal adhesion functions. Furthermore, hallmark proteins of epithelial-mesenchymal transition were enriched in DFT2 EVs relative to DFT1 EVs. These findings were validated in EVs derived from serum s les, revealing that the mesenchymal marker tenascin-C was also enriched in EVs derived from the serum of devils infected with DFT2 relative to those infected with DFT1 and healthy controls. This first EV-based investigation of DFTD increases our understanding of the cancers' EVs and their possible involvement in DFTD progression, such as metastasis. Finally, we demonstrated the potential of EVs to differentiate between DFT1 and DFT2, highlighting their potential use as less-invasive liquid biopsies for the Tasmanian devil.
Publisher: Wiley
Date: 27-02-2021
DOI: 10.1111/ELE.13703
Abstract: Infectious diseases are strong drivers of wildlife population dynamics, however, empirical analyses from the early stages of pathogen emergence are rare. Tasmanian devil facial tumour disease (DFTD), discovered in 1996, provides the opportunity to study an epizootic from its inception. We use a pattern‐oriented diffusion simulation to model the spatial spread of DFTD across the species' range and quantify population effects by jointly modelling multiple streams of data spanning 35 years. We estimate the wild devil population peaked at 53 000 in 1996, less than half of previous estimates. DFTD spread rapidly through high‐density areas, with spread velocity slowing in areas of low host densities. By 2020, DFTD occupied % of the species' range, causing 82% declines in local densities and reducing the total population to 16 900. Encouragingly, our model forecasts the population decline should level‐off within the next decade, supporting conservation management focused on facilitating evolution of resistance and tolerance.
No related grants have been discovered for Manuel Ruiz-Aravena.