ebook ebooks e-book e-books downloaden bei MyEbooks.ch downloaden

West Nile Encephalitis Virus Infection Viral Pathogenesis and the Host Immune Response

:	Michael S. Diamond , edited by I. W. Fong.
:	Michael S. Diamond
:	West Nile Encephalitis Virus Infection Viral Pathogenesis and the Host Immune Response
:	Springer-Verlag
:	9780387798400
:	1
:	CHF 189.80
:

:	Mikrobiologie
:	English

:	485
:	Wasserzeichen/DRM
:	PC/MAC/eReader/Tablet
:	PDF

West Nile virus is a neurotropic flavivirus that has emerged globally as a primary cause of viral encephalitis. Infection of humans and other vertebrate animals is associated with a febrile illness that can progress to a lethal encephalitis or flaccid paralysis syndrome. Its appearance in the Western Hemisphere in 1999 and the corresponding increase in global disease burden over the last decade have been accompanied by intensive study, including the entry of many scientists into the field. Breakthroughs have been made in understanding the unique transmission pattern between the vector and the multiple avian and mammalian hosts and targets. Studies in mammalian systems have dissected the viral and host factors that determine the pathogenesis and outcome of West Nile virus infection. On the basis of these experiments, progress has been made on the identification of genetic factors that predispose to severe human disease. Thus, in a remarkably short period of time, insight has been gained on a wide variety of disciplines related to West Nile virus biology. The aim of this book was to assemble an up-to-date and cutti- edge anthology from the leading experts in the field. The chapters are balanced by submissions from newcomers who have made significant recent contributions with those from established investigators who have dedicated their careers to the study of West Nile virus.

	Preface	6
	Contents	8
	Contributors	17
	1. Global Epidemiology of West Nile Virus	20
	1 Introduction	20
	2 West Nile Virus in Africa, Asia, and Europe	23
	2.1 Africa	23
	2.2 Middle East, Russia, Asia, and Australia	24
	2.3 Europe	25
	3 West Nile Virus in the Americas	26
	3.1 United States	26
	3.1.1 Mosquitoes and Vertebrates	26
	3.1.2 Human Incidence and Distribution	27
	3.2 Canada	30
	3.3 Latin America and the Caribbean	30
	4 Clinical Epidemiology	31
	4.1 Risk Factors Associated with Human Disease	31
	4.2 Transmission Modes	33
	5 Summary	35
	References	35
	2 . West Nile Virus: Molecular Epidemiology and Diversity	43
	1 Overview of WNV Genetic Diversity at a Global Scale	43
	2 Molecular Epidemiology of WNV in the Americas	45
	2.1 Evidence for a Single Point Introduction	45
	2.2 Genetic Conservation and Diversification During Colonization	46
	2.3 Insights into WNV Population Dynamics	48
	2.4 Sampling Bias and Methodological Issues: Impact on Conclusions	49
	2.5 Implications for WNV Pathogenesis	51
	3 Ecology and Phylogeny: WNV Adaptation in the Western Hemisphere	52
	3.1 General Considerations	52
	3.2 Adaptation to Mosquito Hosts	54
	3.3 Adaptation to Avian Hosts	54
	4 Evolutionary Mechanisms in West Nile Virus	55
	5 Summary and Future Studies	56
	References	57
	3 . Vector Biology and West Nile Virus	62
	1 Introduction: Importance of Vector Biology in West Nile Virus Ecology	62
	2 Transmission of West Nile Virus	63
	2.1 Natural Transmission Cycle	63
	2.2 Vector Competence and Vectorial Capacity	64
	2.3 Mosquitoes Involved in Transmission of WNV	66
	2.4 Other Potential Arthropod Vectors	68
	2.5 Role of Vectors in Overwintering	68
	3 Genetics and Molecular Biology of Virus–Mosquito Interactions	70
	3.1 Influence of Mosquito Genetics on WNV Transmission	70
	3.2 Key Interaction: Infection of and Dissemination from the Midgut	70
	3.3 Transmission by Bite: Mosquito Salivary Proteins	71
	3.4 Potential Barriers to Infection: Mosquito Defense Mechanisms	72
	3.5 Pathogenesis in Mosquito Tissues	75
	3.6 Role of Virus Genetics in Vector Interactions	76
	4 Control of WNV Disease: Interruption of the Transmission Cycle	77
	5 Conclusion	78
	References	78
	4. Clinical Manifestations of Neurological Disease	85
	1 Introduction	85
	2 Epidemiology and Risk Factors for WNV Neuroinvasive Disease	86
	3 Clinical Manifestations	88
	3.1 West Nile Meningitis	90
	3.2 West Nile Encephalitis	93
	3.3 West Nile Acute Flaccid Paralysis	97
	3.4 Other Clinical Manifestations	99
	4 Outcomes and Prognoses	100
	5 Therapy of West Nile Virus Infection	102
	References	106
	5. Molecular Biology of West Nile Virus	112
	1 Introduction	112
	2 Virus Classification	113
	3 Genome RNA	113
	4 Virion Morphology and Proteins	114
	5 WNV Replication Cycle	116
	6 Viral Nonstructural Proteins	119
	7 In Vitro Polymerase Assays	127
	8 Conserved Viral RNA Terminal Structures and Sequences	128
	8.1 Conserved Sequences	128
	8.2 Secondary Structures	130
	8.3 Tertiary Structures	131
	9 Host Cell Proteins Interact with the WNV 3¢ Terminal SLs and Facilitate RNA Synthesis	131
	9.1 Cellular Proteins Bind to the 3' (+) SL RNA	132
	9.2 Cellular Proteins Bind to the 3' (–) SL	134
	9.3 Virus Interactions with the Host Cell	136
	9.4 Host Genetic Resistance to Flavivirus-Induced Disease	137
	9.5 Virulence Determinants	138
	10 Conclusions	139
	References	139
	6. Virulence of West Nile Virus in Different Animal Hosts	152
	1 Introduction	152
	2 Classification of West Nile Virus Strains: Antigenic and Nucleotide Sequence Diversity	153
	3 WNV: Natural Hosts, Animal Models and Disease	155
	3.1 WNV Disease in Humans	155
	3.2 Nonhuman Primates	157
	3.3 Avians	157
	3.4 Equines	158
	3.5 Chipmunks, Rabbits, and Tree Squirrels	159
	3.6 Small Animal Models: Mice and Hamsters	159
	4 Molecular Determinants of Natural Virulence Variations Between WNV Strains	160
	4.1 Contribution of Individual Viral-Encoded Proteins to WNV Virulence	160
	4.2 Comparative Studies of WNV Virulence in Mouse and Hamster Models	161
	4.3 Emergence and Characterization of Attenuated WNV Variants in the Americas	162
	4.4 Determinants of Virulence in Avians	163
	5 Summary	164
	References	164
	7. Innate immune Response and Mechanisms of Interferon Antagonism Against West Nile Virus	169
	1 Introduction	169
	2 Recognition of WNV by Cellular Sensors: Activation of the First Wave of the Innate Immune Response	169
	3 INF-alpha and IFN Stimulated Genes (ISGs) Are Essentialfor Survival of WNV Infections	173
	4 Effectors of the IFN Response	174
	5 Viral Antagonism of the IFN Response	176
	6 What Is the Mechanism Responsible for this Inhibition of the IFN Response?	178
	7 Implications for Natural Infections in Humans	178
	References	179
	8. Innate Immune Responses to West Nile Virus Infection	183
	1 Introduction	183
	2 Sensing WNV Infection: Role of Pattern-Recognition Receptors	184
	2.1 Toll-Like Receptors	186
	2.2 RNA Helicases	188
	2.3 Nonconventional PRRs	189
	3 Role of Innate Immune Cells in WNV Infection	189
	3.1 Macrophages	189
	3.2 Dendritic Cells	190
	3.3 Gamma/DeltaT Cells	191
	3.4 NK Cells	192
	4 Cytokines Involved in Innate Responses to WNV Infection	193
	4.1 Macrophage Migration Inhibitory Factor	193
	4.2 IFN- Gamma	195
	4.3 Other Inflammatory Cytokines	195
	5 Concluding Remarks	196
	References	197