(nucleocapsid) RNA-dependent RNA polymerase
Viral envelope
• matrix protein (M1) (具型特异性, Ag性稳定)
• lipid bilayer
membrane protein(M2) spikes
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HA and NA
•病毒的表面抗原
•具亚型特异性
•Ag性不稳而易变
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Structure of influenza virus
Viral envelope
matrix protein lipid bilayer
HA NA
M1 M2
1 2 34 5 6 7 8
segmented ssRNA
(negative sense, 8 or 7 segments)
Typing
• type: A,B,C • subtypes:H1~H15 and N1~N9
Labile and much variable in antigenicity of HA and NA Form of variation
• antigenic drift → median or small epidemic of influenza (point mutation→variant) • antigenic shift → pandemic of influenza
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Ⅲ.Laboratory Diagnosis
1.Isolation of viruses 2.Detection of antibody
(hemagglutination inhibition test) 3.Quick diagnosis
(Immunolabelling technique,PCR)
viral core
PB2
PB1 PA
RNA-dependent RNA polymerase
RNA
NP
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RNPi.e. nucleoca6 psid
structure of virion
Viral core ---helical nucleocapsid
(RNA+ NP = RNP)
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• orthomyxovirus(正粘病毒) • pathogen of influenza
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Outline
➢Biological Properties ➢Pathogenicity and Immunity ➢Laboratory Diagnosis ➢Prophylaxis and Treatment
Chapter 20
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p257
Categories of respiratory viruses
Myxovirus
•orthomyxovirus (influenza virus)
•paramyxoviruses (measles virus,so.on.)
SARS coronavirus(SARS Cov) Other respiratory viruses
virus, parainfluenza virus and
respiratory syncytial virus (RSV)
➢Differ from orthomyxoviruses
larger diameter
different spikes
(HN, H, G and F protein)
nonsegmented ss-RNA
(hemagglutination inhibition)
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Ⅳ.Principle of
Prophylaxis and Therapy
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Paramyxovirus (副粘病毒)
➢Inclusion: measles virus, mumps
obvious CPE
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route of transmission influenza and complication
2.Immunity
anti-HA (SIgA important) specific CMI (CD4+T/CD8+T cell) subtype-specific immunity
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Viral envelope
(MP+lipid bilayer+spike)
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Spikes
• glycoprotein
• surface antigen of virus
* subtype-specific
* labile and variable in antigenicity
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Ⅰ.Biological Properties
1.Shape and structure
Shape d=80-120 nm,spherical
Structure
segmented ㈠ssRNA (易发生基因重组)
Viral core Nucleoprotein(NP) (具型特异性, Ag性稳定)
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Hemagglutination
inhibition test
a.virus+RBC→agglutination of RBC
HA receptoe (hemagglutination)
b.(virus+serum)+RBC
早,晚期血清
absence of agglutina
* Hemagglutinin (HA) HA1, HA2
* Neuraminidase (NA)
function 凝集红细胞
吸附宿主细胞
function 参与病毒释放
具有抗原性
促进病毒扩散
具有抗原性
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2.Typing and Variation
(reassortment→form new subtype)
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3.Cultivation Embryonated eggs inoculation Tissue culture
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Ⅱ.Pathogenicity & Immunity
1.Pathogenicity