1. Viruses Associated with Respiratory Infections
Chapter 20
Viruses Associated with
Respiratory Infections
呼吸道感染病毒

2. Categories of respiratory viruses
Myxovirus •orthomyxovirus
•paramyxoviruses
SARS coronavirus(SARS Cov)
Other respiratory viruses
(influenza virus)
(measles virus,so.on.)

3. Influenza Virus
流行性感冒病毒
• orthomyxovirus(正粘病毒)
• pathogen of influenza

4. Outline Biological Properties Pathogenicity and Immunity
Laboratory Diagnosis
Prophylaxis and Treatment

5. Ⅰ.Biological Properties
1.Shape and structure
 Shape
d= nm,spherical
 Structure
segmented ㈠ssRNA
Nucleoprotein(NP)
RNA-dependent RNA polymerase
(易发生基因重组)
Viral core
(具型特异性, Ag性稳定)
(nucleocapsid)
Viral envelope
• matrix protein (M1) • lipid bilayer
(具型特异性, Ag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) spikes

6. Structure of influenza virus
segmented ssRNA M1
(negative sense,
8 or 7 segments) M2
Viral envelope 1 2 3 4 5 6 7 8
matrix protein
viral core
RNA-dependent RNA polymerase
PB2
lipid bilayer
PB1 PA HA
RNA NA NP
RNPi.e. nucleocapsid

7. helical nucleocapsid structure of virion Viral envelope
Viral core ----
helical nucleocapsid
structure
of virion
(RNA+ NP = RNP)
Viral envelope
(MP+lipid bilayer+spike)

8. Spikes • glycoprotein • surface antigen of virus • 2 types: HA and NA
* subtype-specific
* labile and variable in antigenicity
HA1, HA2
function
* Hemagglutinin (HA) * Neuraminidase (NA)
凝集红细胞 吸附宿主细胞具有抗原性
function
参与病毒释放 促进病毒扩散 具有抗原性

9. 2.Typing and Variation
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 • antigenic shift → pandemic of influenza
(point mutation→variant)
(reassortment→form new subtype)

10. 3.Cultivation
Embryonated eggs inoculation
Tissue culture

11. Ⅱ.Pathogenicity & Immunity
route of transmission
influenza and complication
2.Immunity
anti-HA (SIgA important) specific CMI (CD4+T/CD8+T cell) subtype-specific immunity

12. Ⅲ.Laboratory Diagnosis
1.Isolation of viruses
2.Detection of antibody (hemagglutination inhibition test)
3.Quick diagnosis (Immunolabelling technique,PCR)

13. Hemagglutination inhibition test
a.virus+RBC→agglutination of RBC HA
receptoe
(hemagglutination)
b.(virus+serum)+RBC 
早,晚期血清
absence of agglutination
(hemagglutination inhibition)

14. Ⅳ.Principle of Prophylaxis and Therapy

15. Paramyxovirus (副粘病毒)
Inclusion: measles virus, mumps virus, parainfluenza virus and respiratory syncytial virus (RSV)
Differ from orthomyxoviruses
larger diameter different spikes
(HN, H, G and F protein)
nonsegmented ss-RNA obvious CPE
d= nm
(融合细胞与包涵体)

16. 1.Biological properties
Measles Virus
麻疹病毒
1.Biological properties
(spherical,enveloped virus)
Spikes: HA and HL (haemolysin)
 Nonsegmented ss-RNA (negative sense)
 Single serotype
 Typical CPE in cell culture
HA---凝集猴红细胞,与受体结合; HL---溶血和融合作用

17. 2.Pathogenicity and immunity
• feature of infection
• pathogen of measles
• complication
(viral receptor----CD46 )
(pneumonnia, encephalitis
and SSPE)
 Immunity
(lifelong immunity)

18.  Laboratory diagnosis
 Specific provention
•Artificial active immunity (live attenuated vaccine or MMR)
•Artificial passive immunity

19. Mumps & complications lifelong immunity Artificial active immunity
Mumps Virus
腮腺炎病毒
(pathogen of mumps)
Single serotype
Mumps & complications
lifelong immunity
Artificial active immunity
(live attenuated vaccine , MMR)

20. Parainfluenza Viruses
副流感病毒
5 types
Causes of croup (type 1,2)
Also cause pneumonia in children and common cold in adults
哮吼---急性喉气管支气管炎

21. Respiratory Syncytial Virus
(RSV)
呼吸道合胞病毒
Spike: G and F protein
Pathogenicity •cause bronchiolitis, pneumonia in infants • cause common cold in adults and young children • important pathogen of hospital infection

22. SARS coronavirus SARS 冠状病毒
(SARS Cov)
SARS 冠状病毒
---pathogen of severe acute respiratory syndrome(SARS)
1.Shape and structure
2.Pathogenicity and immunity
d=60~220nm, +ss-RNA，enveloped virus and spike
• source of infection
• route of transmission
• cause SARS
• immunity
patient
近距离飞沫传播为主
有家庭和医院明显聚集现象
3.Diognosis and prophylaxis

23. Other Respiratory Viruses
1.Adenovirus
 naked virus with ds-DNA
and cubic nucleocapsid
 typical CPE and pathogenicity
(p207表:呼吸道感染、眼部感染、腹泻等)
2.Rubella virus
 single antigen type
 cause rubella and congenital rubella
syndrome
(MMR)
3.Rhinovirus
＞114 type
The most important pathogen of common cold