Host Innate Immune Responses to Infection by Avian- and Bat-borne Viruses PDF Download
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Author: Efstathios Giotis
Publisher: Frontiers Media SA
ISBN: 2889666646
Category : Science
Languages : en
Pages : 111
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Author: Efstathios Giotis
Publisher: Frontiers Media SA
ISBN: 2889666646
Category : Science
Languages : en
Pages : 111
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Book Description
Author: Sean Cody Adams
Publisher:
ISBN: 9781303791550
Category :
Languages : en
Pages :
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Book Description
The Influenza A Virus (IAV) employs a variety of strategies in order to disarm the host immune response, most of which are carried out by the non-structural 1 protein encoded in the eighth viral genome segment. One such strategy is to blunt the innate immune response by preventing the expression of the type I interferons (IFN), other pro-inflammatory cytokines and immune-related genes. Disruption of the interferon-signaling pathway is a central component of viral infection in both mammalian and avian hosts. However, there is considerable variability in virus capacity to disrupt this signaling pathway as well as variation between species of the host expression of immune-related genes in response to infection with the same virus. Moreover, the clinical outcomes of viral infection differ among avian species; ducks harbor persistent, asymptomatic infections, where chickens display more robust responses and present symptomatically with respiratory signs, decreased egg production, and mortality. Avian species are not well understood as hosts of IAV. The general roles of avian species in the transmission, perpetuation, and evolution of IAV is well known although detailed information is lacking including knowledge of avian immune responses and their regulation by IAV. As a consequence, IAV from birds are frequently adapted to and subsequently assessed in mammalian hosts such as mice and ferrets for immune function and viral transmission studies, the results of which are extrapolated to encompass the generic non-human response to avian influenza. To address this gap in knowledge regarding the avian response to IAV, the following chapters of this thesis describe the early responses to IAV infection on a molecular signaling level and compare them in cells derived from chickens and ducks. In Chapter 2, by infecting peripheral blood mononuclear cells (PBMC) from avian hosts that have differences in responses to IAV infection and play different roles in the natural history of IAV with the same low pathogenic avian influenza virus, we identified differences in the expressions of key immune-related genes. Interestingly, the cytopathic effect of the virus was evident in chicken cells, whereas duck cells displayed no evidence of infection. Furthermore, the in vitro cytokine and immune-gene expression profiles between the two host's differed. Specifically pro-inflammatory molecules IL-1[beta] and IL-6 were highly upregulated in chicken cells, whereas duck cells expressed baseline levels, and a similar pattern was observed for both IFN-[beta] and IFN-[gamma]. Taken together, these patterns suggest a molecular mechanism for observed clinical presentation. Low pro-inflammatory and IFN levels are consistent with an asymptomatic response to IAV infections in ducks, while the robust responses in chickens are more consistent with symptomatic infections. These findings provide valuable insight into the IFN expression patterns induced by IAV and differences between the responses of avian hosts. A canonical response to avian IAV infections has been reported in mammalian hosts, where the IAV NS1 protein, antagonizes the expression of type I IFN at multiple levels of the cellular pathway. It is less clear how NS1 interacts with avian cellular proteins, and whether viral suppression of IFN expression is similar in birds generally or if the mechanism and magnitude of expression differs between the major classes of avian hosts. To further complicate the issue, the NS1 gene exists as two allelic variants. One variant, the A allele, has been identified in viruses infecting all susceptible hosts, mammalian and avian. The other variant, the B allele, is almost exclusively isolated from viruses infecting avian hosts with few exceptions. The two alleles are only 69% identical at the amino acid level, and the sequence differences imply the two alleles may function differently. The second aim in this body of work was to characterize the in vitro innate immune gene (the type I IFNs and downstream cytokines) expression of chickens, turkeys, and ducks in response to infection with A allele or the B allele reassortant viruses. This study identified key differences and similarities between the two alleles. First, viruses bearing the A allele replicated to higher titers in the cells of chickens and turkeys (species which share a more recent ancestor), whereas viruses bearing the B allele replicated to higher titer in duck cells (species more distantly related to chickens and turkeys). Second, the B allele also suppressed the expression of IFN-[beta] more effectively than did the A allele at a single time point in chicken and turkey cells. The differences between the alleles ended there; both A and B allele NS1 proteins modulated the expression of the other type I IFN and their downstream effector proteins Mx and 2'-5' oligoadenylate synthetase to similar extents. Chimeric constructs of the NS1 gene were used to identify regions of the NS1 gene responsible for the differences in replication titers and the expression of IFN-[beta] in chicken cells between A and B alleles. This assay identified the nucleotides spanning positions 1-164 as responsible for the differences in viral replication, whereas nucleotide positions 164-541 were responsible for the differences in IFN-[beta] expression in chicken cells. Combined, these results form the first comprehensive study of IAV and NS1 alleles in avian species. The final aim of this study was to characterize the geographic distribution, prevalence, and selective pressure driving amino acid changes of the NS1 alleles in viruses isolated from North American chickens, turkeys, and ducks. In addition to online databases, sequences were obtained from the California H6N2 outbreak in chickens, which took place between 2000 and 2005. This study identified a higher than expected proportion of B alleles in circulation from 2002-2012. Interestingly, the H6N2 viruses were associated with a mixed population of viruses bearing either the A or the B allele, which is unusual since other outbreaks were associated with only one NS1 sequence. Lastly, a novel approach to identifying selective pressures was employed by examining the ratio of nonsynonymous to synonymous substitutions of specific functional regions of the NS1 gene and compared to the ratio of the entire gene. This approach identified that the carboxyl terminus of the NS1 gene is undergoing positive selective pressure which is driving variation in this region.
Author: Lin-Fa Wang
Publisher: John Wiley & Sons
ISBN: 1118818733
Category : Science
Languages : en
Pages : 402
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Book Description
Approximately 75% of emerging infectious diseases are zoonoses, and the rate of emergence of zoonotic diseases is on the rise. Bats are being increasingly recognised as an important reservoir of zoonotic viruses of different families, including SARS coronavirus, Nipah virus, Hendra virus and Ebola virus. Understanding bats’ role in emerging zoonotic diseases is crucial to this rapidly expanding area of research. Bats and Viruses: A New Frontier of Emerging Infectious Diseases provides an updated overview of research focusing on bat biology and the role bats play as hosts of many major zoonotic viruses. The text covers bat biology, immunology, and genomics. Chapters also delve into the various major bat-borne virus families, including lyssaviruses, paramyxoviruses, coronaviruses, filoviruses and reoviruses, among others. Edited by leaders in the field, Bats and Viruses: A New Frontier of Emerging Infectious Diseases is a timely, invaluable reference for bat researchers studying microbiology, virology and immunology, as well as infectious disease workers and epidemiologists, among others.
Author: Ricardo Martín Gómez
Publisher: Frontiers Media SA
ISBN: 2889636488
Category :
Languages : en
Pages : 179
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Book Description
Author: Institute of Medicine
Publisher: National Academies Press
ISBN: 0309314003
Category : Medical
Languages : en
Pages : 310
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Book Description
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.
Author: Michele Nancy Maughan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Avian immunology research is expanding quickly due to the growing knowledge base of the chicken cytokines, Toll-Like Receptors (TLRs) and their immune signaling pathways. Our aim was characterize the avian innate immune response to microbial infection by utilizing a pathogenomics approach. By performing microarray experiments using our Avian Innate Immune Microarray (AIIM), we were able to measure the transcriptional host immune response to several important avian pathogens. Furthermore, by performing immunotherapeutic interventions using TLR agonists prior to challenge with highly pathogenic avian influenza virus, we were able to extend survival time of treated birds by 14% (p
Author: Christian C. Voigt
Publisher: Springer
ISBN: 3319252208
Category : Nature
Languages : en
Pages : 601
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Book Description
This book focuses on central themes related to the conservation of bats. It details their response to land-use change and management practices, intensified urbanization and roost disturbance and loss. Increasing interactions between humans and bats as a result of hunting, disease relationships, occupation of human dwellings, and conflict over fruit crops are explored in depth. Finally, contributors highlight the roles that taxonomy, conservation networks and conservation psychology have to play in conserving this imperilled but vital taxon. With over 1300 species, bats are the second largest order of mammals, yet as the Anthropocene dawns, bat populations around the world are in decline. Greater understanding of the anthropogenic drivers of this decline and exploration of possible mitigation measures are urgently needed if we are to retain global bat diversity in the coming decades. This book brings together teams of international experts to provide a global review of current understanding and recommend directions for future research and mitigation.
Author: Sven Klimpel
Publisher: Springer Science & Business Media
ISBN: 3642393330
Category : Medical
Languages : en
Pages : 195
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Book Description
This book gathers contributions by 16 international authors on the phenomenon “bats,” shedding some light on their morphology, the feeding behaviors (insects, fruits, blood) of different groups, their potential and confirmed transmissions of agents of diseases, their endo- and ectoparasites, as well as countless myths surrounding their lifestyle (e.g. vampirism, chupacabras, batman etc.). Bats have been known in different cultures for several thousand centuries, however their nocturnal activities have made them mysterious and led to many legends and myths, while proven facts remained scarce. Even today, our knowledge of bats remains limited compared to other groups in the animal kingdom. Also, their famous ability to avoid collisions with obstacles during their nightly flights with the help of a sophisticated and unique system using ultrasound waves (which are transmitted and received) is as poorly studied as birds finding their way from continent to continent. In recent times, where globalization transports millions of people and goods from one end of the earth to the other, there are increased risks posed by agents of diseases, as a result of which bats have received increasing attention as potential vectors. These suppositions are based on their proven transmission of viruses such as rabies. In dedicated chapters, the book addresses the following topics: • The world of bats • The astonishing morphology of bats • Bats as potential reservoir hosts for vector-borne diseases • Bat endoparasites • Macroparasites – ectoparasites • Glimpses into how bats fly • Blood-licking bats • Vampirism in medicine and culture • Chupacabras and “goat milkers” • Myths on candiru As such, this book provides a broad range of information for all non-experts interested in biological topics, but also for people working in this field, as well as physicians and veterinarians who are confronted with clinical cases, and for teachers and students interested in expanding their knowledge of biology and of past and present cultures.
Author: Eugenia Corrales-Aguilar
Publisher: Caister Academic Press Limited
ISBN: 9781912530144
Category : Medical
Languages : en
Pages : 0
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Book Description
An invaluable reference source for everyone working on bat-borne viruses.
Author: Institute of Medicine
Publisher: National Academies Press
ISBN: 0309131219
Category : Science
Languages : en
Pages : 330
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Book Description
Dr. Joshua Lederberg - scientist, Nobel laureate, visionary thinker, and friend of the Forum on Microbial Threats - died on February 2, 2008. It was in his honor that the Institute of Medicine's Forum on Microbial Threats convened a public workshop on May 20-21, 2008, to examine Dr. Lederberg's scientific and policy contributions to the marketplace of ideas in the life sciences, medicine, and public policy. The resulting workshop summary, Microbial Evolution and Co-Adaptation, demonstrates the extent to which conceptual and technological developments have, within a few short years, advanced our collective understanding of the microbiome, microbial genetics, microbial communities, and microbe-host-environment interactions.
