Date post: | 18-Jan-2016 |
Category: |
Documents |
Upload: | diane-williamson |
View: | 212 times |
Download: | 0 times |
11
20 chapter20 chapter viruses associated with viruses associated with respiratory infections respiratory infections
Department of pathogenic biology
xie-shuixiang
22
ORTHOMYXOVIRUSESORTHOMYXOVIRUSES
• pleomorphicpleomorphic
• influenza types influenza types A,B,CA,B,C
• febrile, respiratory febrile, respiratory illness with illness with systemic symptomssystemic symptoms
33
‘‘ FLU’FLU’
• True influenzaTrue influenza– influenza virus A or influenza virus B (or influenza virus A or influenza virus B (or
influenza virus C infections - much milder)influenza virus C infections - much milder)
• Febrile respiratory disease with Febrile respiratory disease with systemic symptoms caused by a systemic symptoms caused by a variety of other organisms often called variety of other organisms often called ‘flu’ ‘flu’
44
1918-19 Spanish flu 500,000 US20,000,000 world
1957-58 Asian flu 70,000 US
1968-69 Hong Kongflu
34,000 US
THE IMPACT OF INFLUENZATHE IMPACT OF INFLUENZAPANDEMICSPANDEMICS
Deaths:
55
INFLUENZA VIRUSINFLUENZA VIRUS
66
Composition of Influenza Composition of Influenza VirusVirus
1.1.CoreCore RNARNA : : -ssRNA-ssRNA, 8 fragments, 8 fragments NP (nucleoprotein)NP (nucleoprotein) RNA dependent RNA polymeraseRNA dependent RNA polymerase2. envelope2. envelope M proteinM protein lipid envelopelipid envelope sipke hemagglutinin(HA) 5sipke hemagglutinin(HA) 5 neuraminidase(NA) 1neuraminidase(NA) 1
77
M1 protein
helical nucleocapsid (RNA plus NP protein)
HA - hemagglutinin
polymerase complex
lipid bilayer membrane
NA - neuraminidase
type A, B, C : NP, M1 protein sub-types: HAHA or NANA protein
88
NomenclatureNomenclature
Host of originHost of origin
geographical origingeographical origin
strain numberstrain number
parenthesesparentheses
antigenic descriptionantigenic description
of HA and NAof HA and NA
e.g. A/swinee.g. A/swine/Iowa/3/70(H/Iowa/3/70(H11NN11))
A/Hong Kong/1/68(HA/Hong Kong/1/68(H33NN22))
99
Functions of HemagglutininFunctions of Hemagglutinin
• HA causes agglutination of red blood HA causes agglutination of red blood cells.cells.
• Viruses bind to the mucous membrane Viruses bind to the mucous membrane cells by HA1 interacting with cells by HA1 interacting with membrane receptor.membrane receptor.
• Virus’ envelope fuse with cell Virus’ envelope fuse with cell membrane by HA2 forming a fusion membrane by HA2 forming a fusion pore.pore.
1010
S S
S S
S S
cell enzymes
acid pH
HA protein - attachment, HA protein - attachment, fusion fusion
1111
1212
Functions of NeuraminidaseFunctions of Neuraminidase
• NA help the virus to permeate mucin NA help the virus to permeate mucin and escape from “non-specific”inhibitor.and escape from “non-specific”inhibitor.
• NA can increase the number of free NA can increase the number of free virus particles, hence more virus spread virus particles, hence more virus spread from the original site of infection. from the original site of infection.
• NA is important in the final stages of NA is important in the final stages of release of the new virus particle from release of the new virus particle from infected cells.infected cells.
1313
NA protein - neuraminidase NA protein - neuraminidase
1414
ANTIGENIC DRIFTANTIGENIC DRIFT
• Minor changes in antigens due to Minor changes in antigens due to gene mutation in influenza virus.gene mutation in influenza virus.
• HA and NA accumulate mutationsHA and NA accumulate mutations– RNA virusRNA virus
• immune response no longer protects immune response no longer protects fullyfully
• sporadic outbreaks, limited epidemicssporadic outbreaks, limited epidemics
1515
1616
ANTIGENIC SHIFTANTIGENIC SHIFT
• Major changes in antigens due to Major changes in antigens due to gene reassortment in influenza virus.gene reassortment in influenza virus.
• ““ new” HA or NA proteinsnew” HA or NA proteins
• pre-existing antibodies do not protectpre-existing antibodies do not protect
• may get pandemicsmay get pandemics
1717
1818
INFLUENZA A PANDEMICSINFLUENZA A PANDEMICS
Ryan et al., in Sherris Medical Microbiology
1919
where do “new” HA and NA where do “new” HA and NA come from?come from?• 115 types HA5 types HA
• 9 types NA9 types NA– all circulate in birdsall circulate in birds
• pigspigs– avian and humanavian and human
2020
where do “new” HA and NA where do “new” HA and NA come from?come from?
2121
why do we not have why do we not have influenza B pandemics? influenza B pandemics?
• so far no so far no shifts have shifts have been been recordedrecorded
• no animal no animal reservoir reservoir knownknown
2222
TRANSMISSIONTRANSMISSION
• AEROSOLAEROSOL– 100,000 TO 100,000 TO
1,000,000 VIRIONS 1,000,000 VIRIONS PER DROPLETPER DROPLET
• 18-72 HR 18-72 HR INCUBATIONINCUBATION
• SHEDDINGSHEDDING
2323
• DECREASED DECREASED CLEARANCECLEARANCE
• RISK BACTERIAL RISK BACTERIAL INFECTIONINFECTION
• VIREMIA RAREVIREMIA RARE
Lycke and Norrby Textbook of Medical Virology 1983
2424
RECOVERYRECOVERY
• INTERFERON - SIDE EFFECTS INCLUDE:INTERFERON - SIDE EFFECTS INCLUDE:– FEVER, MYALGIA, FATIGUE, MALAISEFEVER, MYALGIA, FATIGUE, MALAISE
• CELL-MEDIATED IMMUNE RESPONSECELL-MEDIATED IMMUNE RESPONSE
• TISSUE REPAIRTISSUE REPAIR– CAN TAKE SOME TIMECAN TAKE SOME TIME
2525
INTERFERONINTERFERON
2626
INTERFERONINTERFERON
antiviral stateantiviral state
antiviral state
antiviral state
2727
INTERFERONINTERFERON
antiviral stateantiviral state
antiviral state
antiviral state
2828
INTERFERONINTERFERON
antiviral stateantiviral state
antiviral state
antiviral state
2929
PROTECTION AGAINST PROTECTION AGAINST RE-INFECTIONRE-INFECTION
• IgG and IgAIgG and IgA– IgG less efficient but lasts longerIgG less efficient but lasts longer
• antibodies to both HA and NA antibodies to both HA and NA importantimportant– antibody toantibody to HA HA more important (can more important (can
neutralizeneutralize))
3030
SYMPTOMSSYMPTOMS
• FEVERFEVER
• HEADACHEHEADACHE
• MYALGIAMYALGIA
• COUGHCOUGH
• RHINITISRHINITIS
• OCULAR SYMPTOMSOCULAR SYMPTOMS
3131
CLINICAL FINDINGSCLINICAL FINDINGS
• SEVERITYSEVERITY– VERY YOUNGVERY YOUNG– ELDERLYELDERLY– IMMUNO-IMMUNO-
COMPROMISEDCOMPROMISED– HEART OR LUNG HEART OR LUNG
DISEASEDISEASE
3232
PULMONARY PULMONARY COMPLICATIONSCOMPLICATIONS• CROUP (YOUNG CHILDREN)CROUP (YOUNG CHILDREN)• PRIMARY INFLUENZA VIRUS PRIMARY INFLUENZA VIRUS
PNEUMONIAPNEUMONIA• SECONDARY BACTERIAL INFECTIONSECONDARY BACTERIAL INFECTION
– Streptococcus pneumoniaeStreptococcus pneumoniae– Staphlyococcus aureusStaphlyococcus aureus– Hemophilus influenzaeHemophilus influenzae
3333
DIAGNOSISDIAGNOSIS
• ISOLATIONISOLATION– NOSE, THROAT SWABNOSE, THROAT SWAB– TISSUE CULTURE OR EGGSTISSUE CULTURE OR EGGS
• SEROLOGYSEROLOGY
• RAPID TESTSRAPID TESTS
• provisional - clinical picture + provisional - clinical picture + outbreakoutbreak
3434
VACCINEVACCINE
• ‘‘ BEST GUESS’ OF MAIN ANTIGENIC BEST GUESS’ OF MAIN ANTIGENIC TYPESTYPES– CURRENTLYCURRENTLY
•type A - H1N1type A - H1N1
•type A - H3N2type A - H3N2
•type Btype B
•each year choose which variant of each each year choose which variant of each subtype is the best to use for optimal subtype is the best to use for optimal protectionprotection
3535
VACCINEVACCINE
• inactivatedinactivated• egg grownegg grown• sub-unit vaccine for childrensub-unit vaccine for children
• reassortant live vaccine approved 2003reassortant live vaccine approved 2003– for healthy persons (those not at risk for for healthy persons (those not at risk for
complications from influenza infection) complications from influenza infection) ages 5-49 yearsages 5-49 years
3636
live vaccine developmentlive vaccine development
adapted from
Treanor JJ Infect. Med. 15:714
3737
TREATMENT - DRUGSTREATMENT - DRUGS
• RIMANTADINE RIMANTADINE (M2)(M2)•type A only, needs to be given earlytype A only, needs to be given early
• AMANTADINEAMANTADINE (M2)(M2)•type A only, needs to be given earlytype A only, needs to be given early
• ZANAMIVIR ZANAMIVIR (NA)(NA)•types A and B, needs to be given earlytypes A and B, needs to be given early
• OSELTAMIVIR OSELTAMIVIR (NA)(NA)•types A and B, needs to be given earlytypes A and B, needs to be given early
3838
NA protein - neuraminidase NA protein - neuraminidase
.. ..
. . ...
..
....
..
..
3939
OTHER TREATMENTOTHER TREATMENT
• REST, LIQUIDS, ANTI-FEBRILE REST, LIQUIDS, ANTI-FEBRILE AGENTS AGENTS (NO ASPIRIN FOR AGES (NO ASPIRIN FOR AGES 6MTHS-18YRS)6MTHS-18YRS)
• BE AWARE OF COMPLICATIONS AND BE AWARE OF COMPLICATIONS AND TREAT APPROPRIATELYTREAT APPROPRIATELY
4040
CORONAVIRUSESCORONAVIRUSES
COLDS AND SARSCOLDS AND SARS
4141
Severe acute respiratory syndrome
(SARS)
4242
SARS Coronavirus, SARS CoVSARS Coronavirus, SARS CoV
• Severe Acute Respiratory Syndrome(SARS)Severe Acute Respiratory Syndrome(SARS) • 2002/112002/11
4343
SARS symtomSARS symtom
• Droplet or osculationDroplet or osculation• Latent periodLatent period :: 2~12d2~12d ,, usually4~5dusually4~5d• Centralization in family and hospital apparentlyCentralization in family and hospital apparently
4444
Biological Biological propertiesproperties
• 60-130nm60-130nm ,, envelope envelope with spikeswith spikes
• +ssRNA+ssRNA ,, 29.7KB29.7KB ,, 114 ORF:RNA4 ORF:RNA polymer- polymer- asease 、、 SS 、、 EE 、、 MM 、、 NN
• Vero cell--CPE Vero cell--CPE
• Infected quadrumana Infected quadrumana –typical SARS –typical SARS symptomsymptom
4545
SARS GenomeSARS Genome
4646
Transmission Transmission and and EpidemiologyEpidemiology
4747
Chinese SARS Chinese SARS epidemiologyepidemiology
4848
4949
Diagnosis Diagnosis
• Mainly depend on the clinic and Mainly depend on the clinic and epidemiologic data epidemiologic data
• Pathogen diagnosisPathogen diagnosis– Isolation and identification of virusIsolation and identification of virus– RT-PCRRT-PCR– ImmunofluorescenceImmunofluorescence 、、 ELISAELISA
• P3 laboratoryP3 laboratory• Pathogen diagnosis is immaturePathogen diagnosis is immature
5050
Prevention Prevention
• SARS CoVSARS CoV 比普通比普通 CoVCoV 抵抗力强,室温下抵抗力强,室温下痰、粪便、尿中可稳定存活痰、粪便、尿中可稳定存活 1~2d1~2d
• 对温度敏感,对温度敏感, 3737ooCC 存活存活 4d4d ,, 5656ooCC 存活存活90m90m ,, 7575ooC30mC30m
• 对含氯消毒剂、过氧乙酸及对含氯消毒剂、过氧乙酸及 UVUV 均敏感,均敏感,• WHOWHO 推荐中效以上的消毒剂,如过氧乙酸推荐中效以上的消毒剂,如过氧乙酸
5151
5252
5353
5454
5555
Pathologic cytoarchitectural changes indicative of diffuse Pathologic cytoarchitectural changes indicative of diffuse alveolar damage, as well as a multinucleated giant cell alveolar damage, as well as a multinucleated giant cell with no conspicuous viral inclusions.with no conspicuous viral inclusions.
5656
5757
ParamyxoviridaeParamyxoviridae
-ssRNA
5858
Koplik's spots on mucosal membranes
Maculopapular rash (extends from face to extremities)
measles (rubeola)
5959
Measles virusMeasles virusmeasles (rubeola)measles (rubeola)
6060
SUB-ACUTE SCLEROSING SUB-ACUTE SCLEROSING PANENCEPHALITIS (SSPE)PANENCEPHALITIS (SSPE)• Very rarely (7 in 1,000,000 cases) Very rarely (7 in 1,000,000 cases) • 1-10 years after initial infection. 1-10 years after initial infection. • progressive, fatal disease. progressive, fatal disease. • defective forms of the virus in the braindefective forms of the virus in the brain
6161
Lab DiagnosisLab Diagnosis
Histopathology of measles pneumonia. Giant cells.
6262
PreventionPrevention
MMRMMR • ((mumpsmumps, , measlesmeasles, , rubellarubella) vaccine ) vaccine
contains live, attenuated forms of all three contains live, attenuated forms of all three of these viruses.of these viruses.
6363
MUMPS VIRUSMUMPS VIRUSMumps Mumps • British "to mump" - to British "to mump" - to
grimace or grin, from grimace or grin, from the appearance of the the appearance of the patient as a result of patient as a result of parotid gland swelling. parotid gland swelling.
• (Note: Other agents can (Note: Other agents can also cause parotitis).also cause parotitis).
6464
• very contagiousvery contagious
6565
RESPIRATORY SYNCYTIAL VIRUSRESPIRATORY SYNCYTIAL VIRUS
spherical or spherical or pleomorphic pleomorphic enveloped viruses enveloped viruses (100-350 nm) with (100-350 nm) with single-strandedsingle-stranded, , negative sense linear negative sense linear RNA RNA
6666
• Infection of cells Infection of cells results in syncytiumresults in syncytium formationformation
• Upper respiratory Upper respiratory infection (‘bad cold’) in infection (‘bad cold’) in older children and adultsolder children and adults
• Lower respiratory Lower respiratory infection- Bronchiolitis infection- Bronchiolitis and/or pneumonia may and/or pneumonia may occur after the upper occur after the upper respiratory infectionrespiratory infection
• Severe infections occur Severe infections occur in infantsin infants ( (2-6m)2-6m)
6767
OthersOthers
6868
ADENOVIRUSADENOVIRUS• non-envelopednon-enveloped• linear double-stranded (ds) linear double-stranded (ds)
DNADNA• Icosahedral capsid, Icosahedral capsid, • capsomerescapsomeres hexons;hexons; at the vertices are 12 at the vertices are 12 pentonspentons, ,
from which a from which a fiberfiber with a terminal with a terminal knob projects. This complex is knob projects. This complex is toxic to cells - causing rounding toxic to cells - causing rounding and death of cells through and death of cells through inhibition of protein synthesis. inhibition of protein synthesis.
6969
• EyeEye
Epidemic Keratoconjunctivitis (EKC)Epidemic Keratoconjunctivitis (EKC), , acute follicular acute follicular conjunctivitisconjunctivitis, pharyngoconjunctival fever, pharyngoconjunctival fever
• Respiratory systemRespiratory system
Common cold (rhinitis), pharyngitis (with or without fever), Common cold (rhinitis), pharyngitis (with or without fever), tonsillitis, bronchitis, pharyngoconjunctival fever, acute tonsillitis, bronchitis, pharyngoconjunctival fever, acute respiratory disease (LRI) respiratory disease (LRI)
• GenitourinaryGenitourinary
Acute hemorrhagic cystitisAcute hemorrhagic cystitis• GastrointestinalGastrointestinal
Gastroenteritis. Gastroenteritis.
7070
Rash
Congenital rubella
cataracts
RUBELLA
7171
RUBELLA (GERMAN MEASLES) VIRUS RUBELLA (GERMAN MEASLES) VIRUS
• Togavirus Togavirus • +ssRNA+ssRNA• Fetal Fetal
damage damage • live vaccine live vaccine
(attenuated (attenuated strain) strain)