1. Respiratory viruses

2. Categories of Respiratory Viruses
Orthomyxoviridae: Influenza virus
Paramyxoviridae : Parainfluenza virus; Mumps virus; Measles; Respiratory syneytical virus
Togaviridae: Rubella Virus
Coronaviridae: Corona Virus; SARS virus
Adenoviridae : human Adenovirus
picornaviridae: Rhino Virus;
Reoviridae:

3. Orthomyxoviridae: Influenza virus
Influenza is a disease caused by Influenza virus ,a member of the Orthomyxoviridae.

4. Genome of Influenza virus
8 negative sense RNA nucleocapsid segments
The 'RNP' (RNA + nucleoprotein) is in a helical form with the 3 polymerase polypeptides associated with each segment.
The segmented genome promotes genetic diversity caused by mutation and reassortment of segments on infection with two different strains

5. Virion spherical/ovoid, 80-120nm diameter,
The inner side of the envelope is lined by the matrix protein, stable type-specific.

6. Virion
The outer surface of the particle consists of a lipid envelope from which project prominent glycoprotein spikes of two types, the haemagglutinin, ~135Å trimer (HA), and neuraminidase, ~60Å tetramer (NA).

7. Haemagglutinin (HA)
Encoded by RNA segment #4
Can agglutinate red blood cells - hence the nomenclature
Cleavage by host-cell protease is required (resulting in HA1 and HA2) for infection to occur
Hemagglutinin glycoprotein is the viral attachment protein and fusion protein , and it elicits neutralizing , protective antibody responses

8. Neuraminadase (NA) Encoded by RNA segment #6
Enzyme that uses neuraminic (sialic) acid as a substrate
Important in releasing mature virus from cells

9. ORTHOMYXOVIRUSES type A, B, C : NP, M1 protein
HA - hemagglutinin
NA - neuraminidase
helical nucleocapsid (RNA plus
NP protein)
lipid bilayer membrane
polymerase complex
M1 protein
type A, B, C : NP, M1 protein
sub-types: HA or NA protein

10. Influenza virus A

11. Replication
Influenza transcribe and replicates its genome in the target cell nucleus
assemble and buds from the plasma membrane

12. Influenza virus

13. Antigen
Soluble antigens: include ribonucleoprotein and M protein which are much stable in antigenicity.
Surface antigens: include HA and NA which are much variable in antigenicity.

14. Types
Influenza viruses are divided into 3 groups determined by the ribonucleoprotein (RNP) antigen and M antigen:
Group A - This group is the cause of epidemics and pandemics and has an avian intermediate host (IH) Group B - This group causes epidemics and has no IH Group C - This group does not cause epidemics and causes mild disease

15. severity of illness
animal reservoir
human pandemics
human epidemics
antigenic changes
segmented genome
amantadine, rimantidine
zanamivir
surface glycoproteins
TYPE A
++++
yes
shift, drift
sensitive 2
TYPE B ++ no
yes
drift
no effect
sensitive 2
TYPE C + no
no (sporadic)
drift
yes
no effect
(1)

16. Subtypes
According to antigenicity of HA and NA, influenza virus is divided into subtypes such as HnNm( H1N2, et al )

17. Variation and Epidemiology
 Antigenic drift: median or small epidemic.
Antigenic shift:large scale epidemic.

18. Antigenic Shift Of Influenza virus
Reassortment of genes is a common feature of Influenza A, but not B or C
When two different "A" viruses infect the same cell, their RNA segments can become mixed during replication
New viruses produced in this way may survive due to a selective advantage within the population

19. Antigenic Drift of Influenza Virus
Constant mutations in the RNA of influenza which lead to polypeptide mutations
Changes are less dramatic than those induced by Shift
If these mutations affect HA or NA they may cause localized epidemics

21. Epidemic

22. where do “new” HA and NA come from?
13 types HA
9 types NA
all circulate in birds
pigs
avian and human

23. where do “new” HA and NA come from?

24. why do we not have influenza B pandemics?
so far no shifts have been recorded
no animal reservoir known

25. Resistence
The particles are relative labile ,not resistant to drying, etc.

26. Pathogenesis
Influenza is characterised by fever, myalgia, headache and pharyngitis. In addition there may be cough and in severe cases, prostration. There is usually not coryza鼻炎(runny nose) which characterises common cold infections.
Infection may be very mild, even asymptomatic, moderate or very severe

27. Transmission Source of infection: patients and carriers. AEROSOL
100,000 TO 1,000,000 VIRIONS PER DROPLET
18-72 HR INCUBATION

28. Aerosol
Inoculation
Of virus

29. NORMAL TRACHEAL MUCOSA
3 DAYS POST-INFECTION
7 DAYS POST-INFECTION

30. SYMPTOMS
FEVER
HEADACHE
MYALGIA(肌痛)
COUGH
RHINITIS(鼻炎)
OCULAR SYMPTOMS

31. PULMONARY COMPLICATIONS
CROUP (YOUNG CHILDREN)
PRIMARY INFLUENZA VIRUS PNEUMONIA
SECONDARY BACTERIAL INFECTION
Streptococcus pneumoniae
Staphlyococcus aureus
Hemophilus influenzae

32. NON-PULMONARY COMPLICATIONS
myositis (rare, > in children, > with type B)
cardiac complications
liver and CNS
Reye’s syndrome
peripheral nervous system

34. Immunity

35. Lab Diagnosis Viral detection: Respiratory secretions
( direct aspirate , gargle , nasal washings )
1. Cell culture in primary monkey kidney or madindarby canine kidney cells
2. Hemagglutination (inhibition)
Hemadsorption (inhibition)
3. IFA/ ELISA

36. Serology
hemagglutination inhibition
Hemadsorption inhibition
ELISA
immunofluoresence
complement fixation.
NT.

37. Prevention
Vaccines at best give about 70% protection. They may sometimes not be effective against the most recently evolved strains because the rate of evolution outpaces the rate at which new vaccines can be manufactured.
This constant antigenic change down the years means that new vaccines have to be made on a regular basis.

38. Types of Vaccine Killed Whole Virus Rather pyrogenic, not used today.
Live Virus Attenuated strains were widely used in Russia but not elsewhere.
Virus Subunit HA extracted from recombinant virus forms the basis of today's vaccines. For example, the WHO Recommendation for Influenza Vaccine, , contains two A strains and one B strain:-[A / Singapore / 6 / 86 (H1N1)+A / Johannesburg / 33 / 94 (H3N2) +B / Beijing / 84 / 93 ]
Synthetic Much research is being done to try and find a neutralising epitope that is more stable, and can therefore be used for a universal vaccine.

39. CDC

40. Attenuated Donor Master Strain
PB2
PB1 PA HA NA NP M NS
Attenuated Donor Master Strain
New Virulent Antigenic Variant Strain X
Attenuated Vaccine Strain: Coat of Virulent strain with Virulence Characteristics of Attenuated Strain

41. Treatment
Amantadine and rimantadine are active against influenza A viruses. The action of these closely related agents is complex and incompletely understood, but they are believed to block cellular membrane ion channels, and inhibit an uncoating step and target the M2 membrane protein

42. PREVENTION - DRUGS RIMANTADINE金刚乙胺 (M2) AMANTADINE金刚烷胺 (M2)
type A only
AMANTADINE金刚烷胺 (M2)
ZANAMIVIR (NA)
types A and B, not yet approved for prevention but studies show effective
OSELTAMIVIR (NA)
types A and B

43. TREATMENT - DRUGS RIMANTADINE (M2) AMANTADINE (M2) ZANAMIVIR (NA)
type A only, needs to be given early
AMANTADINE (M2)
ZANAMIVIR (NA)
types A and B, needs to be given early
OSELTAMIVIR (NA)

44. OTHER TREATMENT
REST, LIQUIDS, ANTI-FEBRILE AGENTS (NO ASPIRIN FOR AGES 6MTHS-18YRS)
BE AWARE OF COMPLICATIONS AND TREAT APPROPRIATELY

45. Paramyxoviridae

46. Paramyxoviridae Genus Human pathogen Morbillivirus Measles virus
Paramyxovirus Parainfluenza viruses,
Mumps virus
Pneumovirus Respirtory syncytical
virus

47. Virion
Large virion consists of a negative RNA genome in a helical nucleocapsid surrounded by an enevlope containing a viral attachment protein
HN of paramyxovirus and mumps virus has hemagglutinin and neuraminidase.
H of measles virus has hemagglutinin activity
G of RSV lacks these activities

48. PARAMYXOVIRUSES pleomorphic HN/H/G glycoprotein SPIKES F glycoprotein
helical nucleocapsid (RNA plus
NP protein)
lipid bilayer membrane
polymerase
complex
M protein

49. PARAMYXOVIRUS FAMILY properties of attachment protein
GENUS
GLYCOPROTEINS
TYPICAL MEMBERS
Paramyxovirus genus
HN, F
HPIV1, HPIV3
Rubulavirus Genus
HPIV2, HPIV4 mumps virus
Morbillivirus genus
H, F
measles virus
Pneumovirus genus
G, F
respiratory syncytial virus

51. Replication , Pathogenesis and Immunity
Virus replicates in the cytoplasm
Virions penetrate the cell by fusion with the plasma membrane
Viruses induce cell-cell fusion, causing multinucleated giant cells
Paramyxoviridae are transmitted in respiratory droplets and initiate infection in the respiratory tract
Cell-mediated immunity causes many of the symptoms but is essential for control of the infection

52. MMR vaccine Composition : live attenuated virus
Measles / Mumps / Rubella
Vaccination schedule: at months and at 4 to 6 years or before junior high school
Efficiency: 95% lifelong immunization with a single dose

54. Measles virus （麻疹病毒）

55. Pathogenesis and Immunity
Childhood infection almost universal, protection resulting from this is probably lifelong. Both man and wild monkeys are commonly infected
In culture, produces characteristic intranuclear inclusion bodies and syncytial giant cells.
Transmission and initial stages of disease similar to mumps, but this virus can also infect via the eye and multiply in the conjunctivae. Viraemia following primary local multiplication results in widespread distribution to many organs.

56. Pathogenesis and Immunity
After a day incubation period
Dry cough, sore throat, conjunctivitis (virus may be excreted during this phase!), followed a few days later by the characteristic red, maculopapular rash and Koplik's spots
Towards the end of the disease, there is extensive, generalized virus infection in lymphoid tissues and skin.

57. viremia

58. DISSEMINATED SPREAD LONGER TIME FOR SYMPTOMS IMMUNE RESPONSE
IF SYMPTOMS DUE TO IMMUNE RESPONSE, USUALLY INFECTIOUS PRIOR TO SYMPTOMS
Adapted from Mims, Playfair, Roitt, Wakelin and Williams
(1993) Medical Microbiology

59. MEASLES - Koplik’s spots
Murray et al. Medical Microbiology

60. Koplik's spots

61. MEASLES - RASH
CDC - B.Rice
Murray et al. Medical Microbiology

62. DISEASE FEVER RESPIRATORY TRACT SYMPTOMS KOPLIK’S SPOTS
rhinorrhea, cough
KOPLIK’S SPOTS
MACULOPAPULAR RASH
T-cells ->endothelial cells
CONJUNCTIVITIS
epithelial cells

63. MEASLES GIANT CELL PNEUMONIA
Murray et al. Medical Microbiology

64. Mims et al., Medical Microbiology 1993

65. MEASLES ENCEPHALITIS 1/1000 cases sequelae deafness seizures
mental disorders

66. SSPE sub-acute sclerosing panencephalitis
inflammatory disease
defective virus
early infection with measles is a risk factor
rare (7/1,000,000 cases of measles)
decrease since vaccination program

69. Treatment No

70. Prevention
Both live and killed vaccines exist. Vaccination with the live attenuated vaccine has been practised since the 1960's with a dramatic decline in the incidence of the disease .
Trivalent live attenuated vaccine (MMR) usually given - all of these viruses best avoided during pregnancy!

71. Mumps virus （腮腺炎病毒）

72. Mumps virus
Droplets spread the infection via saliva and secretions from the respiratory tract.
Incubation period of 2-3 weeks

73. Mumps virus
Malaise and fever is followed within a day by painful enlargement of one or both of the parotid (salivary) glands
A possible complication in males after puberty is orchitis - painful swelling of one or both testicles.
Inflammation of the ovary and pancreas can also occur.
Disease is usually self-limiting within a few days
Aseptic meningitis (usually resolving without problems) or postexposure encephalitis (can prove fatal) are the most serious complications associated with mumps.

74. Prevention and treatment
Treatment: none (passive immunization has been used).
Prevention: one invariant serotype therefore vaccines are viable - both formalin-inactivated and live attenuated exist, the latter now being widely used- see MMR.

75. MUMPS
CDC - B.Rice

76. Mims et al., Medical Microbiology 1993

77. Mims et al., Medical Microbiology 1993

78. Parainfluenza virus （副流感病毒）

79. Important Characteristics
Typing: Four types (1-4) : distinguished antigenically, by cytopathic effect, and pathogenically
Hemeagglutinin and fusion F protein is found in the envelope

80. Pathogenesis and Immunity
Cause acute respiratory infections of man ranging from relatively mild influenza-like illness to bronchitis, croup (narrowing of airways which can result in respiratory distress) and pneumonia; common infection of children.
Transmitted by aerosols.

81. Lab Diagnosis
Nasopharynx specimen is culture in a surrogate cell line in AGMK. Infected cell are detected by hemeadsorption or DFA
DFA also can be done rapidly to identify the agent in direct specimen
Serotypes 1-3 are comfirmed by hemeagglutination inhibition using standardized antisera

82. Treatment No antiviral therapy is available
Nursing the patient in a humidified atmosphere was commonly advised
Dexamethasone地塞米松 and budesonide布德松 have been approved ( for outpatient treatments)

83. Prevention
No, vaccines is not available

84. Respiratory syncytial virus （呼吸道合胞病毒）

85. Important Characteristics
RSV is highly infectious, transmission by respiratory secretions.
Primary multiplication occurs in epithelial cells of URT producing a mild illness. In ~50% children less than 8 months old, virus subsequently spreads into the L.R.T. causing bronchitis, pneumonia and croup.
Has been suggested as a possible factor in cot death and asthma.

86. Pathogenesis and immunity
Disorder Age
Bronchiolitis Fever, cough, dyspnea, and
pneumonia, cyanosis in children younger
or both than 1 year
Febrile rhinitis Children
and pharyngitis
Common cold Older children and adults

87. Lab Diagnosis DFA Cell culture of nasopharyngeal specimen
A rise in antibody titre using ELISA

88. Treatment
Ribavirin aerosol(三(氮)唑核苷,病毒唑) is recommended for pneumonia in infants
RSV - IGIV has been approved for infants born prematurely
IFN

89. Prevention
Currently no effective vaccine! Also, infection does not result in lasting protection (c.f. mumps, measles) therefore repeated infections ('colds') occur throughout life - usually without serious consequences in adults.

90. Adenoviruses （腺病毒）

91. General Concepts
Most Adenovirus infections involve either the respiratory or gastrointestinal tracts or the eye. Adenovirus infections are very common, most are asymptomatic. Most people have been infected with at least 1 type at age 15.

92. Adenovirus

93. Important Characteristics

95. Replication

96. Pathogenesis and Immunity
Disease: At Risk:
Acute Respiratory Illness Military recruits, boarding schools,
Pharyngitis Infants
Gastroenteritis Infants
Conjunctivitis All
Pneumonia Infants, military recruits
Keratoconjunctivitis All
Acute Haemorrhagic Cystitis Infants
Hepatitis Infants, liver transplant patients

97. swimming pool conjunctivitis (游泳池结膜炎;红眼病)
Eye infections characterized by a mild conjunctivitis "swimming pool conjunctivitis" are caused by adenoviruses and have been linked to transmission in contaminated swimming pools.

98. swimming pool conjunctivitis

99. Lab Diagnosis
Isolation of adenovirus can be accomplished in cell cultures derived from epithelial cells
Immunoassays, including fluorescent antibody and enzyme-linked immunosorbent assays, PCR can be used to detect and type the virus in clinical samples and tissue cultures
Serological assays such as CFA, HI, EIA and neutralization techniques have been used to detect specific antibodies.

100. Treatment No

101. Prevention
Inactivated vaccines have been developed and are routinely used for military recruits in some countries

102. Rubella Virus （风疹病毒）

103. General Concepts
Viruses have enveloped single stranded positive-sense RNA.
Replication in cytoplasm and bud at plasma membrane
Cause Rubella( german measles, 3-days measles)

104. Epidemiology
Occurrence: worldwide in prevalence( in winter and spring)
Reservoir: Humans
Mode of Transmission: Vertical transmission in case of CRS/ Infection in nonimmune children is usually transmitted by droplet spread or by direct contact with patients
Who is at risk: Non-immunized children are at risk
Incubation period: 2-3 weeks

105. Pathogenesis
Virus
Rubella enters and infects the nasopharynx and lung and then spreads to the lymph nodes and reticuloendothelial system. The resulting viremia spreads the virus to other tissues and the skin. Circulating antibody can block the transfer of virus at the indicated points. In an immunologically deficient pregnant woman, the virus can infect the placenta and spread to the fetus
Congenital infection

106. EFFECTS ON FETUS HEARING LOSS CONGENITAL HEART DEFECTS NEUROLOGICAL
PYSCHOMOTOR AND/OR MENTAL RETARDATION
OPHTHALMIC
CATARACT, GLAUCOMA, RETINOPATHY

107. EFFECTS ON FETUS thrombocytopenia hepatomegaly splenomegaly
intrauterine growth retardation
bone lesions
pneumonitis

108. EFFECTS ON FETUS
First trimester
65-85% of neonates have sequelae

109. EFFECTS ON FETUS 1964 1969 to present
20,000 infants with permanent problems
6,000 to 30,000 spontaneous abortions
5,000 therapeutic abortions
1969 to present
maximum of 67 cases congential rubella/yr
usually fewer than 10

110. CONGENITAL INFECTIONS
SHED VIRUS FOR A YEAR OR MORE AFTER BIRTH
nasopharynx, urine, feces

111. CONGENITAL INFECTIONS
EYE PROBLEMS
GLANDULAR COMPLICATIONS
diabetes,
thyroid problems
deficiency growth hormone

112. CONGENITAL / VERY EARLY INFECTIONS
PROGRESSIVE RUBELLA PANENCEPHALITIS

113. Lab Diagnosis
Current rubella infection, in pregnant women can be confirmed by 4-fold rise in specific antibody titer between acute and convalescent-phase serum specimens by ELISA
The Dx of CRS in the newborn may be confirmed by the presence of specific IgM antibody.

114. Treatment
There is no antiviral therapy available

115. Prevention
A single dose of live, attenuated rubella vaccine elicits a significant antibody response in approximately 98%-99% of vaccinated individuals
It should not be given to immunocompromised patients

116. Coronavirus （冠状病毒）

117. Important Characteristics
Virion: Spherical, nm in diameter, helical nucleocapside
Genome: +ssRNA, linear, nonsegmented, 27-30kb, infectious
Proteome: two glycoproteins and one phosphoprotein. Some viruses contain a third glycoprotein (hemagglutinin esterase)
Envelope: contains large, widely spaced, club-or petal- shaped spikes. crown-like

118. Virion structure
S-Spike glycoprotein: receptor binding, cell fusion, major antigen
M-Membrane glycoprotein: transmembrane - budding & envelope formation

119. Pathogenesis and Immunity
These viruses infect a variety of mammals & birds. The exact number of human isolates are not known as many cannot be grown in culture.
They cause: common colds and have been implicated in gastroenteritis in infants.
Transmitted by aerosols of respiratory secretions

120. Rhinovirus （鼻病毒）

121. Important Characteristics
Rhinoviruses are picornaviruses similar to enteroviruses but differ from them in having a buoyant density in cesium chloride of 1.40 g/ml and in being Acid-labile
Rhinoviruses are isolated commonly from the nose and throat but very rarely from feces.
These viruses cause upper respiratory tract infections, including the common cold

122. Reovirus (呼肠孤病毒)

123. Important Characteristics
Virion: Icosahedal, 60-80nm in diameter, double capsid shell
Genome: dsRNA
Envelope: none
Diseases: Acute respiratory tract infection and Gastrointestinal infections