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69 Cards in this Set
- Front
- Back
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Orthomyxoviridae genus
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Influenza A
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Orthomyxoviridae influenzvirus A
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H7N7 - horse- noncirc
H3N8 - horse,dog H1N1, H3N2, H1N2, H3N1, (pig, human) H5N1 - cat, human |
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HA =
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hemagglutinin
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NA -
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Neuraminidase
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Orthomyxoviridae reservoir
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migratory birds
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Cats get influenza from
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humans
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Influenza characteristics
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spherical or filamentous
enveloped with spikes segmented genome helical symmetry |
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HA binds to
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sialic acid residues causing fusion of membrane with endosome (neutralizing epitopes)
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H2 (ion channel)
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allows acidification of the neuroprotein to uncoat the RNA. Blocked by amantadine
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NA cleaves
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sialic acid residues, major antigenic determinant, liquifaction of mucus, blocked by pseltamivir (tamiflu)
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Influenza enters the cell via
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receptor mediated endocytosis
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To be activated, HA must be
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cleaved with trypsin and trypsin like proteases in respiratory tract.
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Once Ha bind to sialic acid residues, the virus particle is
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endocytosed
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With influx of H+ via M2 channel,
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HA fusion protein exposed
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In the nucleus of the cell the viral genome
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steal the cap from host RNA, inactivating it and activating viral mRNA.
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mechanisms of genetic variation of influenza virus
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point mutations
genetic reassortment genetic recombination |
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Point mutations are due to
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random changes in single nucleotide, due to lack of proofreading of RNA polymerase, multiple point mutations, needed for new strain, passage through multiple hosts necessary
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Genetic reassortment
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swapping of entire gene segments
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Gentic recombination
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swapping of small regions of gene segments, single or mixed infection
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Antigenic drift
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point mutations, minor changes
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antigenic shift
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major shift
totally new virus usually from coinfection by 2 virus' creating new 3 strain |
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Equine Influenza A diagnosis
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History
Hi, ELISA - kit virus isolation Test is best 1 - 2 days before sick |
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Equine Influenza A treatment
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rest, minimum of 3 weeks
supportive care |
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Equine Influenza A control
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isolation of new horses
vaccination of H3N8 and H7N7 via killed and intranasal MLV |
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Influenza A canine subtype
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H3N8
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H3N8 infected _____ before it infected ______
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horses
dogs |
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Influenza A H3N8 has a high____ and a low ______
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morbidity
mortality |
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fever, nasal discharge, mild to severe respiratory disease in dogs
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Influenza A - Canine influenza
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H3N8 may be mistaken for
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infectious thracheobronchitis ( kennel cough in dogs)
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Mild form of H3N8 presents as
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low grade fever
persistent soft moist productive to dry cough |
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Severe form of H3N8
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high-grade fever, increased respiration, pneumonia
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Canine influenza diagnosis via
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HI - serum
PCR - may miss other serot Virus isolation - difficult ELISA kit |
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Canine influenza TX
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supportive care
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Canine influenza control
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cleaning/disinfecting, isolation of dogs with respiratory disease, inactivated vaccine,
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Influenza A virus in swine
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H1N1 H3N2
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Influenza A has explosive outbreaks in the
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fall and winter
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Influenza A virus in a pig is a ______ disease
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acute, contagious, respiratory disease of pigs
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Fever, nasal discharge coughing dyspnea, high morbidity, rapid recovery 5 - 7 days in pigs
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Influenza A in pigs
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Swine influenza may develop
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bronchopneumonia
interstitial pneumonia |
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Diagnosis of Swine flu
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History
H1N1, N3N2 virus isolation HI |
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Influenza Swine flu Tx
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supportive care
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Influenza A control
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management, reduce stress
vaccination. |
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Influenza A Avian flu causes
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contagious respiratory and systemic disease
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Influenza A avian flu infects
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chickens and turkey
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Influenza A virus avian flu types
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Low pathogenic avian flu
High pathogenic avian flu |
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Low pathogenic avian influenza causes
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sneezing, coughing sinusitis, decreased egg production, low morbidity, and mortality
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LPAI may be
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subclinical
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HPAI is also called
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fowl plague
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HPAI causes
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severe systemic disease, high mortality (90 - 100 %). H5N2, H7N1, H5N1 (avian flu)
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hemorrhage, and edema, cyanosis of combs and wattles, tracheal subcutaneous skeletal muscle and visceral hemorrhage
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HPAI
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HPAI involves what body systems?
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respiratory, digestive and urogenital systems, CNS
sudden death |
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Influenza A avian flu reservoir
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migratory waterfowl
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Influenza A avian flu is shed in
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feces
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Influenza A reservoir infections in
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intestinal tract, no disease or subclinical enteric infections
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LPAI may mutate to
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HPAI
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Influenza A avian virus diagnosis
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clinical signs
AGID - govt approved test ELISA HI |
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Influenza A virus avian flu is a
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reportable disease
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Influenza A virus prevention
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vaccination (killed and recombinant vax)
quarantine of affected flocks, depopulation, disinfection of premises |
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Influenza A is a problem in Asia because of
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the close proximity of pigs, poultry and people.
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Influenza has its own
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Polymerase - 3 different types
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Influenza A virus - equine influenza
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H3N8
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Equine Influenza infects
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young horses - 2 - 8 month
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Equine Influenza is a
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mild disease with high morbidity
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Equine Influenza A replication in
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respiratory epithelial cells, imparied cilia,
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Equine Influenza A clinical signs
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fever, conjunctivitis,nasal discharge, dry cough, laryngitis, tracheitis, bronchitits,
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Equine Influenza A is highly
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contagious with rapid spread via aerosol, recovery in 7 - 10 days to 2 - 3 weeks
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Equine Influenza A diagnosis
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history, HI
ELISA (Human test) PCR 1 - 2 days before sick |
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Equine Influenza A TX
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rest, supportive care
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Equine Influenza A Control
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Isolation of new horses,
VX |
