#10 Respiratory viruses Flashcards
Transmission of respiratory viruses
Transmission→ Replication in URT→ Upper ans sometimes lower infections and diseases
Picornavirdae virus family:
genome:
env:
diseases
+RNA,
non enveloped
Rhinovirus, Coxsackie virus, echovirus, enterovirus
Coronavirdae
genome
enveloped
diseases
+RNA
eneveloped
-Coronavirus, SARS-CoV, MERS-CoV
Coronavirus, SARS-CoV, MERS-CoV examples of
Coronavirdae
+ RNA, enveloped
Rhinovirus, Coxsackie virus, echovirus, enterovirus examples of
Picornavirdae
Orthomyxovirdiae
genome
enveloped
viruses
-RNA
env
Influenza A, B, C virus
Influenza A, B, C virus are what family
orthomyxovirdae
-RNA env
Parmyxovirdae
genome
envelope
viruses
-RNA
env
Parainfluenza, respiratory syncytial, metapneumovirus, Hendra and Nipavirus, measles virus
Parainfluenza, respiratory syncytial, metapneumovirus, Hendra and Nipavirus, measles virus
all Parmyxovirdae virsuse
-RNA, env
INfluenza A, B and C family of viruses
Orthomyxovius
Genus of influenza A, B and C
(Thogotovirus)
Typing of influenza A, B C
Based on matrix and nuceloprotein antigens
Subtyping of influenza based on
Based on Hemagluttin and Neuramidase
H1N1 or H2N2
Influenza stucture:
envelope virus with matrix proteins that adds structure
: key for attachement and fusion to cellular membrane
Hemagluttinin
key for release of protein virions
Neuramidase:
Ribonuclear protein of influenza has____ individual segments of RNA. Complexed with proteins key in polymerase activity
8
Genome of influenza and affect on what it brings with it to host cells
- RNA
- there is a (-) sense RNA thus virus has to carry a polymerase with it to begin replication
Drift: minor change in either
HA or NA or both
Drift: HA mutations are primarily found in the ______combining sites in the HA protein
4 antibody
*Drifts cause______ We’ll see same influenza subtype (H3N2 for example) with dif strains
EPIDEMICS!!!
Shift: major_____ shifts.
occur infrequently either
antigenic
in HA alone or NA as well.
Cause of genetic shift
D/t gene reassortment btwn human and animal strain
Shifts cause _______
*Pandemics
example of shift causing pandemic
H1N1 vs H2N2 or in 2009 the swine flu (H1N1) see avian and human coinfect a pig which has both α2,3 and α2,6 receptors
Pathogenesis of Influenza:
- acute respiratory disease
- infects ciliated epithelial cells lining URT, trachea and bronchi
- Replication of virus responsible for destruction of respiratory epithelium
- Cell damage d/t virus activated CTL
- Viremia is NOT a mjor role in pathogenesis
Influenza causes
___________
infects ________ lining URT/trachea/bronchi
-acute respiratory disease
ciliated epithehlial cells
What is responsible for destruction of epithelium during influensa
- Replication of virus responsible for destruction of respiratory epithelium
- Cell damage d/t virus activated CTL
Role of viremia in influenza patho
Viremia is NOT a mjor role in pathogenesis
Common Pathogenesis if influenza
Aerosol inocculation of virus→ Replicates in repsiratory tract (causes antiB, Tcell response, Interferon induction)→ Desquamination of mucus→Influenza syndrome
Aerosol inocculation of virus→ Replicates in ________ (causes antiB, Tcell response, Interferon induction)→______ of mucus→Influenza syndrome
repsiratory tract
Desquamination
Influenza pathology:
Less frequent: Secondary bacterial infection
lead to pneumonai, primary viral pneumonia and CNS/mscl involvment
Host reponst to influenzaL
Antibody and T cell response:
T cell response and Interfuron induction:
provides for future protection
push for influenza syndrome
Pathogensis of influeza
Infterfeuron induction:
Patho change in respiratory:
Cell mediated:
Infterfeuron induction: 1 day
Patho change in respiratory:6 days
Cell mediated: day 4
Lab detection of influenza
Virus in respiratory secreations:
Rise in virus-antiB:
1 day
day 7
Clincal disease of influenza
Symptoms, influenza: 2 days
Incubation:
2 days before symtpoms
Acute influenza in adults
Rapid onset fever, malaise, myalgia, sore throat, nonproductive cough
Acute influenza kids
Acute disease sim to adults but higher fever, GI symptoms (pain and vomit) otitis media, myositis, more frequent croup
Complications of virus (influenza
Primary viral pneumonia, secondary bacterial pneumonia, myosistis and cardiac involvement
Neurologic syndromes: Guillain-Barre, Encephalopathy, Encephalitis, Reye Syndrome
Clincal signs/epidemiology and then Lab diagnostics for INfluenza:
- rapid antiG capture—
- rt-PCR tells us
detects nucleoprotein (NP) or both influenza A and B virus w/in 15 mins
what type we are dealing with
Overview on Replication
- Binds to sialic acid receptors–>Endocytosed and fuses with vesicle mmb and uncoated
- ->Transcription/replication of genome occurs IN THE NUCLEUS (most RNA’s do this in cytosol)
- ->Viral proteins synthesized and helical nucleocapsid segments form and assicate with M1 protein-lined membranes containing M2 and the HA and NA glycoproteins
- ->Virus buds from plasma membrane with 8-11 nucleocapsid segs
influenza will bind to ______ to get endocytosed and fuses with vesical membrane to get uncoated
sialic acid
Transcription and replication of genome for influenza occur in_____
Nucleus (most RNAs don’t do this)
Viral proteins of influenza synthesized and helical nulceuocapsid segments form and associated with:
M1 proteins lined proteoins containing M2 as well as HA and NE
When influenza virus buds, has ____ nucleocapsid segments
8-11