Download or read book The Effect of Amphibian Host Ecology and Evolution on the Pathogen Dynamics of Ranavirus written by Lauren V. Ash and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging infectious diseases threaten amphibian species around the globe. Ranavirus (Family: Iridoviridae) is associated with the majority of amphibian deaths in North America, with some species exhibiting mass mortality events in short periods of time. In contrast, some amphibian species show the capacity to resist or tolerate infection. Resistant individuals exhibit reduced infection intensity, while tolerant individuals display reduced fitness effects given the infection intensity. My research focused on how amphibian host dynamics at community, population, and individual-level scales relate to the wide variation in Ranavirus prevalence and severity. Through my work, I documented the first reports of Ranavirus in the state of Vermont and recorded the species Frog-virus 3 (FV3) at relatively low prevalence in many amphibian species and life stages across wetlands. Overall, my results contribute to our understanding of host-pathogen dynamics, particularly for this deadly amphibian disease.I investigated the relationship between host biodiversity and Ranavirus in my first chapter. Previous studies in other systems have documented a negative relationship, with host diversity 'diluting' disease risk, while other systems have observed the opposite, with diversity amplifying disease risk. Although I hypothesized a dilution effect, I found the presence and abundance of certain amphibian species (e.g., Pseudacris crucifer) positively related to and amplified Ranavirus prevalence. However, other species (e.g., Notophthalmus viridescens) were associated with reduced population or community prevalence, and many individuals harbored asymptomatic infections. Little is known about the capability for these more resistant and tolerant species to serve as reservoirs, or sources of infection, for other more susceptible species. The American bullfrog (Lithobates catesbeianus) is a species that has shown experimental resistance and tolerance to FV3. For my second chapter, I provided the first assessment of concomitant infection of Ranavirus and helminth macroparasites in invasive populations of bullfrogs in South America. In Brazil, bullfrogs are farmed for their meat and have invaded the Atlantic Forest, which houses many of Brazil's endemic anuran species. Asymptomatic Ranavirus infection was common in invasive bullfrogs, suggesting they can serve as sources of infection to native species. Co-infection by helminth macroparasite taxa was also common. I found a significant negative relationship between Ranavirus viral load and nematode abundance, and Ranavirus-infected bullfrogs had lower total macroparasite abundances. This suggests a trade-off in immune response may be occurring: individuals who may be effective at controlling macroparasite abundances could be more susceptible to pathogen infection and vice-versa. Individual host immune response most likely contributes to the variation in Ranavirus susceptibility and mortality observed even within populations. The Major Histocompatibility Complex (MHC) generates and modulates acquired immune response in all jawed vertebrates. For my final chapter, I used an experimental approach to determine whether MHC haplotypes were associated with the mortality and viral loads of experimentally infected wood frog (L. sylvaticus) tadpoles. I detected 24 unique haplotypes in 33 of the most susceptible and resistant individuals, which formed 4 haplotype supergroups. One supergroup (VT-02) had more resistant and fitter individuals, while another had higher mortality (VT-03). I detected diversifying selection on multiple amino acid sites across the MHC gene in all supertypes, indicating positive selection on the MHC gene may reflect pressure from other sources.

Download or read book Evolution and Ecology of an Amphibian Emerging Infectious Disease written by Pierre Echaubard and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Host-pathogen investigations have conceptually evolved during the last two decades, from a basic and descriptive approach to a current hypothesis-driven and a more theoretical discipline shaped by evolutionary biology. Our deeper understanding of the elements influencing the mutual selective pressures that the host and the pathogens exert on each other, together with recent conceptual advances, currently position this field of research at the frontier between ecology and evolution. Recent theoretical considerations define hostpathogens systems as an evo-eco mosaic comprised of evolutionary and ecological attributes in turn underlying the context-dependent nature of the system dynamic. Therefore, investigations of host-pathogen interactions should integrate the diversity of the systems drivers by using an integrative approach in order to elucidate both coevolutionary trajectory and epidemiological dynamic of the system. In this thesis, such a framework is used to investigate Amphibian/ranavirus interactions. Ranaviruses are emerging pathogens known to have caused amphibian die-offs on five continents with the greatest number of reported mortality events documented in North America and Europe. Despite an increasing understanding of ranaviral disease properties, ranavirus disease dynamics in the environment remain poorly understood. For instance, the influence of potential abiotic and biotic mechanisms including temperature, local landscape features, larval developmental stages, host density and genetic variability as well as genotypic interactions between the host and the pathogen has on the prevalence and virulence of the virus remains to be elucidated. In order to improve our knowledge regarding these specific determinants of ranaviral disease, I designed a combination of manipulative laboratory experiments and a field mensurative survey using the ranid amphibian Lithobates (Rana) pipiens as the host model for this system. I observed that populations of amphibian hosts inhabiting urbanized landscapes suffered from significant decline in genetic diversity in turn promoting the accrued infection by the ranavirus (manuscript 1). Complementary analysis using two amphibian host species, L.pipiens and L.sylvaticus, and three ranavirus strains revealed significant variation among hosts for their susceptibility to ranavirus, and significant variation among ranavirus strains for infectivity. I also showed that specific amphibian/ranavirus interactions might have a tighter coevolutionary history than other combinations, resulting in sharper mutual coadaptations and the potential for frequency-dependent selection to operate in this system. However, the coevolutionary trajectories in this host-pathogen system are dependent on the temperature conditions in which the interaction takes place. Amphibian/ranavirus interactions outcomes iv are therefore temperature, host, and pathogen genotype-dependent suggesting that the range of infection outcomes in this system is potentially large (manuscript 2). Further, I observed that increasing animal holding density is detrimental for host fitness as mortality rate is higher, day of death earlier, development longer, and growth rate significantly lower when tadpoles are experimentally exposed to ranavirus in high holding density situations. These results paralleled a linear increase of detrimental effects when ranavirus doses increased in low density conditions, with control tadpoles having a significantly higher overall relative fitness. However, this pattern was not observed in high density conditions, where the effects of increasing ranavirus dose were limited, revealing non-trivial density-dependence of virulence expression (manuscript 3). Finally, ranavirus infection rate varied with the host developmental stage as the host immune system clears the infection over the course of individual host development. However the intensity of the clearing depends on both the timing and number of ranavirus exposures (manuscript 4). Overall the results described in my thesis suggest that ranavirus virulence depends on a diversity of ecological, epidemiological, and evolutionary determinants. The underlying complexity of ranavirus.

Download or read book Ranaviruses written by Matthew J. Gray and published by Springer. This book was released on 2015-04-27 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book on ranaviruses. Ranaviruses are double-stranded DNA viruses that cause hemorrhagic disease in amphibians, reptiles, and fish. They have caused mass die-offs of ectothermic vertebrates in wild and captive populations around the globe. There is evidence that this pathogen is emerging and responsible for population declines in certain locations. Considering that amphibians and freshwater turtles are suitable hosts and the most imperiled vertebrate taxa in the world, ranaviruses can have significant impacts on biodiversity and ecosystem function. Additionally, many fish that are raised in aquaculture facilities and traded internationally are suitable hosts; thus, the potential economic impact of ranaviruses is significant. Ranaviruses also serve as a model for replication and gene function of large double-stranded DNA viruses. There is an urgent need to assemble the contemporary information on ranaviruses and provide guidance on how to assess their threats in populations. Through the Global Ranavirus Consortium, 24 experts from six countries were organize to write this volume, the first book on ranaviruses. The book begins with a discussion on the global extent of ranaviruses, case histories of infection and disease in ectothermic vertebrates, and current phylogeny. Basic principles of ranavirus ecology and evolution are covered next, with a focus on host-pathogen interactions and how the virus emerges in its environment. There are two chapters that will discuss the molecular biology of ranaviruses, host response to infection, and the genes responsible for immune system evasion. One chapter establishes standards for testing for infection and diagnosing ranaviral disease. The book ends by providing guidance on how to design ranavirus surveillance studies and analyze data to determine risk, and discussing the role of the Global Ranavirus Consortium in organizing research and outreach activities.

Download or read book Ranaviruses written by Matthew J. Gray and published by Springer. This book was released on 2016-10-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book on ranaviruses. Ranaviruses are double-stranded DNA viruses that cause hemorrhagic disease in amphibians, reptiles, and fish. They have caused mass die-offs of ectothermic vertebrates in wild and captive populations around the globe. There is evidence that this pathogen is emerging and responsible for population declines in certain locations. Considering that amphibians and freshwater turtles are suitable hosts and the most imperiled vertebrate taxa in the world, ranaviruses can have significant impacts on biodiversity and ecosystem function. Additionally, many fish that are raised in aquaculture facilities and traded internationally are suitable hosts; thus, the potential economic impact of ranaviruses is significant. Ranaviruses also serve as a model for replication and gene function of large double-stranded DNA viruses. There is an urgent need to assemble the contemporary information on ranaviruses and provide guidance on how to assess their threats in populations. Through the Global Ranavirus Consortium, 24 experts from six countries were organize to write this volume, the first book on ranaviruses. The book begins with a discussion on the global extent of ranaviruses, case histories of infection and disease in ectothermic vertebrates, and current phylogeny. Basic principles of ranavirus ecology and evolution are covered next, with a focus on host-pathogen interactions and how the virus emerges in its environment. There are two chapters that will discuss the molecular biology of ranaviruses, host response to infection, and the genes responsible for immune system evasion. One chapter establishes standards for testing for infection and diagnosing ranaviral disease. The book ends by providing guidance on how to design ranavirus surveillance studies and analyze data to determine risk, and discussing the role of the Global Ranavirus Consortium in organizing research and outreach activities.

Download or read book Host pathogen Dynamics in a Changing Environment written by Catherine L. Searle and published by . This book was released on 2011 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Infectious diseases are a growing concern for both humans and wildlife. The negative effects of infectious disease have been exemplified by the recent global amphibian population declines associated with disease outbreaks. Although multiple pathogens and factors play a role in these declines, the aquatic fungal pathogen, Batrachochytrium dendrobatidis (Bd), has received considerable attention due to its substantial contribution to amphibian population declines around the world. Bd prevalence and severity appears to be increasing worldwide, either from recent anthropogenic spread of the pathogen or from changes in the environment that have altered host-pathogen dynamics. This dissertation explores the factors that affect host susceptibility to Bd. I first tested the effects of hormonal stress on susceptibility to Bd (Chapter 2). Using corticosterone, the major chronic stress hormone in amphibians, I was able to mimic the physiological effects of stress without altering other factors that may affect the host-pathogen relationship. I exposed three species of larval amphibians to corticosterone for two weeks to induce chronic stress before challenging them with exposure to Bd. I found that exposure to corticosterone did not alter infection prevalence or severity in any species, indicating that chronically elevated levels of corticosterone do not affect susceptibility to Bd. I next examined the interactive effects of the ubiquitous stressor, ultraviolet-B radiation (UVB), and host infection by Bd (Chapter 3). UVB can cause lethal and sublethal effects in amphibians, including increased susceptibility to pathogens. In outdoor mesocosms, I used ambient levels of UVB to stress larval amphibians while simultaneously exposing them to Bd. Although exposure to UVB increased mortality, it did not alter infection. To investigate the effects of community structure on infection prevalence and severity, I studied how six anuran species (frogs and toads) differed in susceptibility to Bd (Chapter 4). I experimentally exposed post-metamorphic amphibians native to North America to Bd under identical laboratory conditions. All species tested had higher rates of mortality when exposed to Bd compared to unexposed controls. However, the species differed widely in their rates of Bd-associated mortality, even though there was no difference in infection levels among species. I also found that within species, the relationship between body size and infection varied, indicating physiological differences in the way that amphibian species respond to pathogen infection. Finally, I studied the effects of the amphibian host community on infection. I experimentally exposed larval amphibians to Bd after manipulating host density and species richness in the laboratory (Chapter 5). I recorded five measures of disease risk and found a dilution effect where greater species richness decreased disease risk, even after taking into account changes in density. Together with Chapter 4, this study emphasizes the need to understand the effects of the community on host-pathogen dynamics. This dissertation provides insight into the effects of stress and community structure on disease dynamics. Although there has been a great effort to understand Bd since it was discovered, the ecology of Bd remains relatively unknown. My research represents an important step in understanding the host-pathogen relationship in a changing environment.

Download or read book Evolutionary Ecology of Amphibians written by Gregorio Moreno-Rueda and published by CRC Press. This book was released on 2023-06-30 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amphibians are the oldest tetrapod group and show an astonishing diversity in lifestyles, many of them being unique. However, globally, they are on a decline. Hence, their study is fundamental to understanding the evolution of diversity and conserving them. This book, authored by experts from around the world, summarizes the current knowledge on the evolutionary ecology of amphibians. The book treats biological concepts related to the evolution, ecology, physiology, immunology, behaviour, and morphology of amphibians in their different states. This book constitutes an actualized work indispensable for evolutionary ecologists and herpetologists.

Download or read book Crossroads of Stress and Disease written by Emily Marie Hall and published by . This book was released on 2016 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the primary questions of disease ecology is how do environmental conditions influence host-pathogen dynamics. From a physiological perspective, disease susceptibility of hosts can be worsened by the immunosuppressive effects of chronic environmental stress. However, while environmental stress is implicated in the emergence of infectious diseases in wildlife, finding a causal relationship between an environmental stressor, disease susceptibility and outbreaks in wild populations still remains a challenge. Here, we took an integrative approach to test the hypothesis that elevated salinity caused by road runoff of de-icing salts increases the occurrence of disease outbreaks within the wood frog-ranavirus host-pathogen system in northeastern Connecticut, USA. First, we characterized the physiological effects of road runoff in natural populations and found larvae exhibited slower growth and sluggish behavior, and adult males showed severe water retention and elevated baseline stress hormones. Next, to assess pathogen prevalence in pond communities, we validated a technique to measure ranavirus DNA in pond water (environmental DNA). We found ranavirus was ubiquitous in our study region, but die-offs of larvae occurred more often in high salinity ponds. In addition, the timing of die-offs coincided with increases in temperature and the occurrence of susceptible developmental stages. Lastly, we conducted a set of mechanistic experiments to determine whether elevations in salinity causes increases in disease-induced mortality and ranavirus transmission. Ultimately, when dealing with the additional perturbation of infection, salt-stressed individuals had greater mortality. Further, road salt exposure increased the glucocorticoid response to infection, infection intensity, and viral shedding. Therefore, osmotic stress increases transmission and mortality from infection, leading to an exponential increase in prevalence and infection intensity in roadside ponds. Together these studies demonstrate a causal relationship between a sub-lethal stressor which deteriorates health to the point that infections are lethal, and the likelihood of die-offs in larval amphibian populations. This dissertation demonstrates the importance of combining physiology, ecology, and epidemiology frameworks in designing studies to identify causal relationships between environmental change and disease. With this information, we can better advise conservation efforts about the importance of monitoring ranaviruses in wildlife and to mitigate the negative effects of road salt runoff.

Download or read book The Effects of an Emerging Pathogen on Amphibian Host Behaviors and Interactions written by Barbara A. Han and published by . This book was released on 2009 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contemporary environmental change encompasses massive biodiversity loss and increasing numbers of emerging diseases worldwide. As part of a global biodiversity crisis, amphibians are disappearing at unprecedented rates. Batrachochytrium dendrobatidis is an emerging infectious pathogen prominently associated with many declines. Chapter 1 reviews the past decade of research on this system and highlights areas where knowledge is notably lacking. Host behavior remains a crucial determinant of host-pathogen dynamics yet studies addressing the effects of Batrachochytrium on amphibian behaviors are virtually nonexistent. Remaining chapters examine behavioral responses of host species to Batrachochytrium. Chapter 2 examines how ancient behaviors that have persisted in amphibians for millions of years change with exposure to Batrachochytrium. I examined thermoregulatory behavior in tadpoles of four species (Pseudacris regilla, Rana aurora, Bufo boreas, Rana cascadae), and aggregation behavior in two species that school as tadpoles (B. boreas, R. cascadae). Results suggest that some amphibians will continue seeking optimal temperatures and continue aggregating regardless of infection risk. I discuss the importance of behavioral plasticity and evolutionary inertia in interpreting host behavioral responses to infection. Chapter 3 examines Batrachochytrium dynamics when multiple host species interact. I manipulated infection status in tadpoles of three naturally co-occurring hosts (P. regilla, B. boreas, R. cascadae) in various combinations and measured growth, survival and infection severity. There were strong interactions between species combinations and infection leading to pathogen-mediated mutualism and competition. Results also suggest that both species richness and species identity may be important factors moderating a dilution effect in this system. Coexisting, interacting hosts must also contend with predators in a community. Chapter 4 explores Batrachochytrium-induced changes in antipredator behaviors in four species (P. regilla, R. aurora, B. boreas, R. cascadae). I also examined whether antipredator behaviors increased survivorship in the presence of lethal predators in R. cascadae, R. aurora. Exposure to Batrachochytrium changed activity rate and refuge use in Bufo, but not in the other species. Nonselective predation of Batrachochytriumexposed prey by susceptible predators adds an unexplored dimension of complexity to this system. Chapter 5 summarizes the ecological implications of studies presented in this dissertation.

Download or read book Wildlife Disease Ecology written by Kenneth Wilson and published by Cambridge University Press. This book was released on 2019-11-14 with total page 693 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces readers to key case studies that illustrate how theory and data can be integrated to understand wildlife disease ecology.

Download or read book Environmental Influences on Host pathogen Dynamics of the Amphibian Chytrid Fungus written by Julia C. Buck and published by . This book was released on 2013 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: The causes of the global biodiversity crisis are varied and complex. Anthropogenic threats may act in isolation, or interact additively or synergistically with each other or with natural stressors to affect sensitive taxa. The recent emergence of many infectious diseases in wildlife has brought attention to the role of disease in population declines and species extinctions. Both abiotic and biotic components of the environment may mitigate or exacerbate effects of pathogens on their hosts through direct or indirect mechanisms. The effects of the environment on host-pathogen dynamics are complex, context-dependent, and in need of further examination. One particularly sensitive group, amphibians, is at the leading edge of the sixth mass extinction. The emerging infectious disease (EID) chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatis (Bd), is implicated in population declines and extinctions of amphibians globally. My disseration addresses questions pertaining to environmental influences on disease dynamics of Bd. As described in chapter 1, various abiotic and biotic components of the environment may affect host-pathogen dynamics of Bd, resulting in changes to the dynamics of Bd transmission and spread. Chapter 2 examines the influence of an abiotic factor, the insecticide (carbaryl) and three different assemblages of larval Pacific treefrogs (Pseudacris regilla) and Cascades frogs (Rana cascadae) on host-pathogen dynamics of Bd within a community context. I found separate effects of each treatment on amphibian growth and development, but no interactive effects among the treatments. However, Bd appeared to reduce phytoplankton abundance and increase periphyton biomass, an unexpected result that merited further investigation. One possible explanation for the results described in chapter 2 is that zooplankton might consume Bd zoospores, the infective stage of the pathogen, a hypothesis that I examine in chapter 3. I conducted laboratory experiments and confirmed the presence of Bd zoospores in the gut of Daphnia sp. through quantitative PCR and visual inspection. I discuss conservation implications of this finding. To determine whether predation on Bd zoospores by zooplankton could reduce infection in amphibians, I conducted a mesocosm experiment, which is described in chapter 4. I found complex effects on species interactions: competition between larval Cascades frogs and zooplankton for phytoplankton resources reduced phytoplankton concentration, zooplankton abundance, and survival of amphibians. These effects were diminished in the presence of Bd, suggesting that zooplankton may have at least partially substituted Bd zoospores for phytoplankton in their diet, thus stimulating competitive release. However, competitive effects between zooplankton and larval amphibians overshadowed indirect positive benefits of zooplankton predation on Bd zoospores. In chapter 4, competitive effects between zooplankton and larval amphibians for phytoplankton suggested that host-pathogen dynamics might be affected by the host???s supply of resources. Chapter 5 describes a mesocosm experiment that examined how eutrophication might affect Bd-infected Pacific treefrogs and other members of the aquatic community. Nutrient additions caused increased algal growth, which benefitted herbivorous larval amphibians. Larvae exposed to Bd altered their growth, development, and diet, and allocated resources differently than unexposed individuals. However, nutrient supplementation did not alter the response of larval amphibians to Bd. As described in chapter 6, consideration of hosts and pathogens as functional members of the ecological communities in which they exist can lead to important insights in host-pathogen dynamics. My PhD research may contribute to control measures for the emerging infectious disease chytridiomycosis.

Download or read book Infectious Disease Ecology written by Richard S. Ostfeld and published by Princeton University Press. This book was released on 2010-12-16 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: News headlines are forever reporting diseases that take huge tolls on humans, wildlife, domestic animals, and both cultivated and native plants worldwide. These diseases can also completely transform the ecosystems that feed us and provide us with other critical benefits, from flood control to water purification. And yet diseases sometimes serve to maintain the structure and function of the ecosystems on which humans depend. Gathering thirteen essays by forty leading experts who convened at the Cary Conference at the Institute of Ecosystem Studies in 2005, this book develops an integrated framework for understanding where these diseases come from, what ecological factors influence their impacts, and how they in turn influence ecosystem dynamics. It marks the first comprehensive and in-depth exploration of the rich and complex linkages between ecology and disease, and provides conceptual underpinnings to understand and ameliorate epidemics. It also sheds light on the roles that diseases play in ecosystems, bringing vital new insights to landscape management issues in particular. While the ecological context is a key piece of the puzzle, effective control and understanding of diseases requires the interaction of professionals in medicine, epidemiology, veterinary medicine, forestry, agriculture, and ecology. The essential resource on the subject, Infectious Disease Ecology seeks to bridge these fields with an ecological approach that focuses on systems thinking and complex interactions.

Download or read book Studies in Viral Ecology Volume 1 written by Christon J. Hurst and published by John Wiley & Sons. This book was released on 2011-06-20 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains the ecology of viruses by examining their interactive dynamics with their hosting species (in this volume, in microbes and plants), including the types of transmission cycles that viruses have evolved encompassing principal and alternate hosts, vehicles, and vectoring species. Examining virology from an organismal biology approach and focusing on the concept that viral infections represent areas of overlap in the ecologies of the involved species, Viral Ecology is essential for students and professionals who either may be non-virologists or virologists whose previous familiarity has been very specialized.

Download or read book New Frontiers of Molecular Epidemiology of Infectious Diseases written by Serge Morand and published by Springer Science & Business Media. This book was released on 2011-09-08 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular epidemiology has recently broaden its focuses due to the development of molecular tools but also by incorporating advances of other fields such as mathematical epidemiology, molecular ecology, population genetics and evolution. Facing new risks of emerging and re-emerging infectious diseases that are threats for humans and their livestock, the objectives of molecular epidemiology include: - the development of molecular tools, genotyping and gene expression - the incorporation of concepts and results of population genetics of infectious diseases - the integration of recent advances in theoretical epidemiology and evolutionary ecology of diseases - a better understanding of transmission for the development of risk factors analyses. This book will demonstrate how the latest developments in molecular tools and in epidemiology can be integrated with studies of host-pathogen interactions. Besides a strong theoretical component, there will also be an emphasis on applications in the fields of epidemiology, public health, veterinary medicine, and health ecology. Students and researchers in the fields of epidemiology, animal and human health, evolutionary ecology, parasitology are the main potential readers of the book, as well as a broader audience from veterinary medicine and conservation.

Download or read book Emerging Viral Diseases written by Institute of Medicine and published by National Academies Press. This book was released on 2015-03-19 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past half century, deadly disease outbreaks caused by novel viruses of animal origin - Nipah virus in Malaysia, Hendra virus in Australia, Hantavirus in the United States, Ebola virus in Africa, along with HIV (human immunodeficiency virus), several influenza subtypes, and the SARS (sudden acute respiratory syndrome) and MERS (Middle East respiratory syndrome) coronaviruses - have underscored the urgency of understanding factors influencing viral disease emergence and spread. Emerging Viral Diseases is the summary of a public workshop hosted in March 2014 to examine factors driving the appearance, establishment, and spread of emerging, re-emerging and novel viral diseases; the global health and economic impacts of recently emerging and novel viral diseases in humans; and the scientific and policy approaches to improving domestic and international capacity to detect and respond to global outbreaks of infectious disease. This report is a record of the presentations and discussion of the event.

Download or read book Freshwater Biodiversity written by David Dudgeon and published by Cambridge University Press. This book was released on 2020-05-21 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growing human populations and higher demands for water impose increasing impacts and stresses upon freshwater biodiversity. Their combined effects have made these animals more endangered than their terrestrial and marine counterparts. Overuse and contamination of water, overexploitation and overfishing, introduction of alien species, and alteration of natural flow regimes have led to a 'great thinning' and declines in abundance of freshwater animals, a 'great shrinking' in body size with reductions in large species, and a 'great mixing' whereby the spread of introduced species has tended to homogenize previously dissimilar communities in different parts of the world. Climate change and warming temperatures will alter global water availability, and exacerbate the other threat factors. What conservation action is needed to halt or reverse these trends, and preserve freshwater biodiversity in a rapidly changing world? This book offers the tools and approaches that can be deployed to help conserve freshwater biodiversity.

Download or read book Family Iridoviridae Molecular and Ecological Studies of a Family Infecting Invertebrates and Ectothermic Vertebrates written by V. Gregory Chinchar and published by MDPI. This book was released on 2019-10-01 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ranaviruses and other viruses within the family Iridoviridae, infect a wide range of ecologically and commercially important ectothermic vertebrates, i.e., bony fish, amphibians, and reptiles, and invertebrates, including agricultural and medical pests and cultured shrimp and crayfish, and are responsible for considerable morbidity and mortality. Understanding the impact of these various agents on diverse host species requires the combined efforts of ecologists, veterinarians, pathologists, comparative immunologists and molecular virologists. Unfortunately, investigators involved in these studies often work in discipline-specific silos that preclude interaction with others whose insights and approaches are required to comprehensively address problems related to ranavirus/iridovirus disease. Our intent here is to breakdown these silos and provide a forum where diverse researchers with a common interest in ranavirus/iridovirus biology can profitably interact. As a colleague once quipped, “Three people make a genius.” We are hoping to do something along those lines by presenting a collection of research articles dealing with issues of anti-viral immunity, identification of a potentially novel viral genus exemplified by erythrocytic necrosis virus, viral inhibition of innate immunity, identification of novel hosts for lymphocystivirus and invertebrate iridoviruses, and modelling studies of ranavirus transmission. Collectively these and others will exemplify the breadth of ongoing studies focused on this virus family.

Download or read book Amphibian conservation action plan proceedings IUCN SSC Amphibian Conservation Summit 2005 written by and published by IUCN. This book was released on 2007 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: