Chapter 20

Categories of respiratory virusesCategories of respiratory viruses

MyxovirusMyxovirus ••oorrthomyxovirusthomyxovirus

••paramyxovirusesparamyxovirusesSARS coronavirusSARS coronavirus(SARS Cov)(SARS Cov) Other respiratory virusesOther respiratory viruses

(influenza virus)

(measles virus,so.on.)

p257

• orthomyxovirus( 正粘病毒 )

• pathogen of influenza

OutlineOutlineBiological PropertiesBiological PropertiesPathogenicity and ImmunityPathogenicity and ImmunityLaboratory DiagnosisLaboratory DiagnosisProphylaxis and TreatmentProphylaxis and Treatment

1.Shape and structure1.Shape and structure

StructureStructured=80-120 nm,spherical ShapeShape

segmented ㈠ ssRNANucleoprotein(NP)RNA-dependent RNA polymerase

Viral coreViral core

•• matrix protein (M1) •• lipid bilayer

(nucleocapsid)

Viral envelopeViral envelope

(( 易发生基因重组易发生基因重组 ))

(( 具型特异性具型特异性 , Ag, Ag 性稳性稳定定 ))

(( 具型特异性具型特异性 , Ag, Ag 性稳定性稳定 ))

HA and NA • 病毒的表面抗原 •具亚型特异性 • Ag 性不稳而易变

membrane protein(M2) membrane protein(M2) spikesspikes

ⅠⅠ.Biological Properties.Biological Properties

1 2 43 5 6 7 8

RNANA

HA

RNPi.e. nucleocapsid

NP

segmented ssRNA

Structure of influenza virusStructure of influenza virus

M1M2

lipid bilayer PB2

PB1PA

(negative sense,8 or 7 segments)

RNA-dependent RNA polymerase

viral coreviral core

Viral envelopeViral envelopematrix protein

Viral core ----Viral core ---- helical nucleocapsidhelical nucleocapsid

(RNA+ NP = RNP)

structurestructure of virionof virion

Viral envelopeViral envelope

(MP+lipid bilayer+spike)

SpikesSpikes •• glycoproteinglycoprotein

•• surface antigen of virussurface antigen of virus

•• 2 types: HA and NA2 types: HA and NA

* subtype-specific * labile and variable in antigenicity

* Hemagglutinin (HA) * Neuraminidase (NA)

HA1, HA2 function

function

凝集红细胞 吸附宿主细胞具有抗原性

参与病毒释放 促进病毒扩散 具有抗原性

2.Typing and Variation2.Typing and VariationTypingTyping

• type: A,B,C • subtypes:H1~H15 and N1~N9

Labile and much variable inLabile and much variable in antigenicity of HA and NAantigenicity of HA and NA Form of variationForm of variation

• antigenic drift → median or small epidemic of influenza • antigenic shift → pandemic of influenza

(point mutation→variant)(point mutation→variant)

(reassortment→form new subtype)(reassortment→form new subtype)

3.Cultivation3.CultivationEmbryonated eggs inocEmbryonated eggs inoc

ulationulationTissue cultureTissue culture

ⅡⅡ.Pathogenicity & Immunity.Pathogenicity & Immunity

1.Pathogenicity1.Pathogenicity

route of transmission influenza and complication

anti-HA (SIgA important) specific CMI (CD4+T/CD8+T cell) subtype-specific immunity

2.Immunity2.Immunity

ⅢⅢ.Laboratory Diagnosis.Laboratory Diagnosis

1.Isolation of viruses1.Isolation of viruses

2.Detection of antibody (hemagglutin2.Detection of antibody (hemagglutination inhibition test)ation inhibition test)

3.Quick diagnosis (Immun3.Quick diagnosis (Immunolabelling technique,PCR)olabelling technique,PCR)

HemagglutinationHemagglutination inhibition testinhibition test

a.virus+RBC→agglutination of RBCa.virus+RBC→agglutination of RBC(hemagglutination)

b.(virus+serum)+RBCb.(virus+serum)+RBC

absence of agglutination(hemagglutination inhibition)(hemagglutination inhibition)

HA receptoe

早早 ,, 晚期血清晚期血清

ⅣⅣ.Principle of .Principle of Prophylaxis and Therapy Prophylaxis and Therapy

ParamyxovirusParamyxovirus (( 副粘病毒副粘病毒 )) Inclusion: measles virus, mumps viInclusion: measles virus, mumps vi

rus, parainfluenza virus and respirrus, parainfluenza virus and respiratory syncytial virus (RSV)atory syncytial virus (RSV)

Differ from orthomyxovirusesDiffer from orthomyxoviruseslarger diameter different spikes(HN, H, G and F protein)nonsegmented ss-RNA obvious CPE

d=150-300nmd=150-300nm(( 融合细胞与包涵体融合细胞与包涵体 ))

1.Biological properties1.Biological properties Spikes: HA and HL (haemolysin)Spikes: HA and HL (haemolysin)

Nonsegmented ss-RNA (negative sense)Nonsegmented ss-RNA (negative sense)

Single serotypeSingle serotype

Typical CPE in cell cultureTypical CPE in cell culture

HA---HA--- 凝集猴红细胞凝集猴红细胞 ,, 与受体结合与受体结合 ; HL---; HL--- 溶血和融合作溶血和融合作用用

(spherical,enveloped virus)

2.Pathogenicity and immunity2.Pathogenicity and immunity

PathogenicityPathogenicity• feature of infection• pathogen of measles

• complication (viral receptor----CD46 )(viral receptor----CD46 )

(pneumonnia, encephalitis (pneumonnia, encephalitis and SSPE)and SSPE)

(lifelong immunity)

ImmunityImmunity

Specific proventionSpecific provention••Artificial active immunity (live Artificial active immunity (live

attenuated vaccine or MMR) attenuated vaccine or MMR)

••ArtificialArtificial passive immunitypassive immunity

Laboratory diagnosisLaboratory diagnosis

Single serotypeSingle serotypeMumps & complicationsMumps & complicationslifelong immunitylifelong immunityArtificial active immunityArtificial active immunity

(live attenuated vaccine , MMR)

(pathogen of mumps)(pathogen of mumps)

5 types5 typesCauses of croup (type 1,2)Causes of croup (type 1,2)

Also cause pneumonia in children aAlso cause pneumonia in children and common cold in adultsnd common cold in adults

哮吼 --- 急性喉气管支气管炎

Spike: G and F proteinSpike: G and F proteinPathogenicity Pathogenicity ••caca

use bronchiolitis, pneumonia in infause bronchiolitis, pneumonia in infants nts •• ca cause common cold in adults and younuse common cold in adults and young children g children •• important pathogen of hospital important pathogen of hospital infectioninfection

(RSV)

(SARS Cov)(SARS Cov)

---pathogen of severe acute respir---pathogen of severe acute respiratory syndrome(SARS)atory syndrome(SARS)

1.Shape and structure1.Shape and structure

2.Pathogenicity and immunity2.Pathogenicity and immunity

d=60~220nm, +ss-RNA ， enveloped virus and spike

• source of infection• route of transmission• cause SARS• immunity

patientpatient

近距离飞沫传播为主近距离飞沫传播为主有家庭和医院明显聚集现象有家庭和医院明显聚集现象

3.Diognosis and prophylaxis 3.Diognosis and prophylaxis

Other Respiratory VirusesOther Respiratory Viruses 1.Adenovirus1.Adenovirus

naked virus with ds-DNA naked virus with ds-DNA and cubic nucleocapsid and cubic nucleocapsid typical CPE and pathogenicity typical CPE and pathogenicity

2.Rubella virus2.Rubella virus single antigen typesingle antigen type cause rubella and congenital rubella cause rubella and congenital rubella syndromesyndrome (MMR)(MMR)

3.Rhinovirus3.Rhinovirus ＞＞ 114 type114 type The most important pathogen of common cold

(p207 表 : 呼吸道感染、眼部感染、腹泻等 )