Term
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Definition
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| infleunza A effects what sp? |
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Definition
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Definition
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| does influenza A have an ENV? |
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Definition
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Term
| peplomers of influenza A = |
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Definition
prominent:
HA - haemaglutin
NA - Neuramidase |
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Term
| nucelocapsid of influenza A = |
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Definition
| 8 helical capsids segments containing -ssRNA with a RNApol attached |
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Term
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Definition
| 8 -ssRNA, no 5'cap, each of the 8 -ssRNA have an RNA pol attached |
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Term
| can -ive ssRNA be directly translated into proteins? |
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Definition
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Term
| function of HA peplomer of influenza A = |
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Definition
| ID ligand on host cell and bind to host cell surface |
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Term
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Definition
1. sialic acid binding site
2. hinge region - activated by host protease which cuts hinge = allows peplomers to fold down= virus closer to host cell mb-enable fusion to occur
3. fusion peptide = allows viral ANV to fuse with endosome mb = viral content released into cell |
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Term
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Definition
affects host range
as HA is diff in mammals and birds |
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Term
| what can restrict what cells influenza A virus infect? |
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Definition
| host cell has to have proteases to cleave hinge region |
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Term
| endocytosis of influenza A by |
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Definition
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Term
| cap snatching of influenza A = |
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Definition
virus takes a bit of RNA duplex from host cell to act as a primer for viral RNA as viral RNA has no cap
steals hosts cap
messes up host cells ability to make RNA due to cap snatching |
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Term
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Definition
| makes +ssRNA and then mRNA = protein synth |
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Term
| some virus mRNA gies ti golgi body to make... |
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Definition
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Term
| virus leaves host cell via... |
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Definition
| ...endocytosis from luminal cell surface of resp epi cells |
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Term
| how does influenza A avoid hosts immunity? |
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Definition
| infects cell, quickly replicates and then leaves cell on luminal side = leave cells |
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Term
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Definition
| cut sialic acid and influenza A virus free from eachother when influenza A virus is leaving the cell |
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Term
| 6 of influenza A genome segments = |
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Definition
| single ORF - produce 1 protein |
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Term
| 6 of influenza A genome segments = |
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Definition
| single ORF - produce 1 protein |
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Term
| how many ORFs in the 8 segments of -RNA in influenza A? |
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Definition
6 of virus genome segments = 1 ORF = produce 1 protein
2 of virus genome segments have 2 diff mRNAs and encode 2 proteins each = make 4 proteins in total
so in total 14 viral proteins are made |
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Term
| genome segments 1, 2, and 3 make |
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Definition
| RNA pol and cap snatching proteins |
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Term
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Definition
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Term
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Definition
| nucleoprotein - make nucleocapsid |
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Definition
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Definition
| other virus ENV associated proteins |
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Term
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Definition
| NSPs - block IFN induction and function |
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Term
| spread of influenza A by... |
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Definition
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Term
| influenza A infects cells of |
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Definition
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Term
| spread of influenza A in the body is... |
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Definition
| ...localised due to luminal budding |
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Term
| what kills influenza A virus? |
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Definition
| dehydration = disrupts ENV and kills influenza A |
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Term
| cytopathic influenza A causes... |
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Definition
-rapid cell death - wipe out epi & cilia
-inflam
-cytokine and IFN response
-sickness behaviour
-fever
-incr mucous secretion and no ciliary movement = accum of mucous in airway
-sensitisation of nociceptors
-pain
-sneezing coughing |
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Term
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Definition
1. virus isolation
2, serology (get strong Ab response to influenza As HA and NA)
3. agglutination by HA - so add specfic Ab that inhibits HA and stop agglutination = influenza A +
4. rapid virus Ag test kit |
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Term
| how do you use a rapid virus Ag test kit? |
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Definition
1. nasal swab
2. lysis of sample
3. detect nucleoprotiens
+ = useful
- = could still be influenza + = limitation of test, not very specific |
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Term
| all serotypes of influenza occur in what sp... |
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Definition
| ...waterfowl (espec ducks) |
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Term
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Definition
| spread in water well cause little dz orofaecal dz (in GIT) |
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Term
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Definition
spread in water well
cause little dz
orofaecal dz (in GIT) |
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Term
| mammalian influenza thought to have derived from... |
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Definition
| ...avian influenza even though avian influenza is hard to grow in mammalian tissue and vice versa |
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Term
| influenza in chickes in spread by.... |
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Definition
| ...aerosol (like mammals, as chickens cant swim, so dont get spread by water) |
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Term
| antigenic drift of influenza occurs due to... |
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Definition
| ...accumulation of point mutations, which occurs rapidly as RNA pol has no proof reading function |
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Term
| antigenic drift may lead to... |
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Definition
...
1. failure of protection by existing neutralising Abs
2. altered/enhanced virus pathogenicity |
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Term
| avian influenza outbreaks called |
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Definition
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Term
| highly virulent avian influenza strains usually have... |
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Definition
...H5 or H7
(different to viruses that usually infect humans) |
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Term
| avian influenza targets... |
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Definition
| ...all cells (all cells able to cleave HA hinge region and therefore become infected) |
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Term
| less virulent strains of avian influenza cause... |
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Definition
| ...resp dz or production loss in chickens and turkeys |
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Term
| swine influenza is more prevelant at wahts time of yr? |
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Definition
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Term
| spread of swine influenza = |
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Definition
| due to intro of new flock or airborne |
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Term
| why is biosecurity so imp in controlling swine influenza? |
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Definition
| humans share some of the same strains of influenza virus as pigs and therefore can spread the virus from farm to farm if dont have gd biosecurity measures |
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Term
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Definition
| outbrrak of acute febrile (fever) URT dz with seconadary pneumonia |
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Term
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Definition
1. virus isolation in embryonated eggs
2. haemagglutin(HA) inhibition test
3. rising Ab titre
4. PCR |
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Term
| new virulent strains of avian influenza may arise from... |
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Definition
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Term
| pnnsylvania outbreak of avian influenza due to... |
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Definition
| ...single aa change in hinge region of HA in exisiting poultry virus - altered cell trpism from resp cells to all cells |
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Term
| whats more pathogenic, H1N1 swine influenza strain, or H3N2 swine influenza strain? |
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Definition
| H1N1 (recent swine influenze from mexico seen in Uk pigs) |
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Term
| reasortment H1N2 swine influenza has been found in what 2 countries? |
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Definition
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Term
| recombination events of influenza virus occur more commonly in... |
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Definition
| ...china whre theres close proximity of pigs, ducks, poultry and humans |
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Term
| type 1 equine influenza = |
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Definition
| last outbreak in 1979, but Ab studies suggest still in circulation |
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Term
| type 2 equine influenza = |
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Definition
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Term
| antigenic drift of type 2 equine influenza = |
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Definition
| seen in N China, has avian genes in it. SHows potential of avian influenza to infect horses, which in turn can lead to reassortment |
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Term
| are humans more likely to be infected with avian or swine influenza virus? |
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Definition
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Term
| vacc against equine influenza |
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Definition
| yes. But only protects against dz, can have vacc horse infected with influenza with influenza still replicating in host cells |
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Term
| equine influenza virus is spread by... |
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Definition
| ...contact and is secreted b4 clinical symptoms arise |
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Term
| acute URT dz with equine influenza = |
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Definition
1. fever
2. depression
3. cough
4. nasal discharge
5. symptoms exacerbated by excer
6. recovery within 2-3wks |
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Term
| severity of equine influenza varies with... |
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Definition
| ...host age and immune status |
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Term
| yards where outbreaks occur must be... |
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Definition
| ...quarantined for at least 4wks after last infection found |
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Term
| Ab response/protection against influenza = |
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Definition
| neutralising Abs mainly against HA (stop primary infection), but also against NA = stop spreading= no clinical dz if cant spread along URT |
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Term
| ADCC response to influenza = |
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Definition
mainly NKcells or C' lysis
only effective once got inflam response is ADCC effective (as birus buds on luminal surface) |
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Term
| cytotoxic Tcell against what in influenza |
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Definition
nucleoprotein. Most abundant protein
Imp in claering infection, but takes time to get going = few days to a wk |
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Term
| IgA in combating influenza infection = |
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Definition
only on luminal side once influenza infection has stim secretory IgA. NOt there b4 for protection :(
ONce infected get memory cells = faster incr in secretory IgA |
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Term
| innte immunity against influenza = |
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Definition
| systemic IgG and cytotxic cells |
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Term
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Definition
1. inactivated vacc - relies on neutralising IgG against HA
therefore neccessary to update vacc to ensure effective against latest strain - need to keep up with antigenic drift
2. ISCOM vacc |
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Term
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Definition
| Immune Stimulatory COMplex induce cytotoxic Tcell response more durable/long response - >yrs prtection (but jockey club says need annual boosters) |
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Term
| antiviral drugs against influenza = |
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Definition
1. amantidine
2. oseltamivir |
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Term
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Definition
block m2 ion channle and prevent uncoating of virus
stop virus infecting host cell |
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Term
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Definition
inhibit NA
(when vet if involved in high virulence avian influenza outbrak vacc self with this) |
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