Orthomyxoviridae Flashcards
Main genera of the Orthomyxoviridae
Influenza A-D, Isavirus, Thogotovirus, Quaranjavirus
Orthomyxoviridae envelope
Yes
Orthomyxoviridae nucleocapsid
Helical
Orthromyxoviridae morphology
Usually spherical or pleomorphic, long filamentous forms occur
Orthomyxoviridae genome
RNA, segmented
Orthomyxoviridae replication
In the nuclei
Important virulence factors of Orthomyxoviridae
Hemagglutinin and neuraminidase
Hemagglutinin
Glycoprotein that allows Orthomyxoviridae to attach cells.
Has two chains.
Causes multiple RBC to clump together
Hemagglutinin chain
1st chain binds to sugar molecules on the cell surface
2nd chain attacks the cell
Neuraminidase
Allows virus to escape from cells by breaking them
Liquefacts mucus-> transport on the mucociliary clearance in airways from bottom to up
Influenzavirus A
respiratory infections on wide host range (aquatic organisms-> mammals)
Influenzavirus B
infects humans and seals
Influenzavirus C
Mild respiratory symptoms in humans and swine
Infuenzavirus D
Infects swine and cattle
Thogotovirus
ticks spread to humans and livestock
Quaranjavirus
Ticks, birds, sometimes humans
Isavirus
Infectious salmon anemia
Ag shift in influenza viruses
in a and b every 2-3 years, ensures presence of immunologically susceptible people
Transmission of influenzaviruses
aerosol
transmission of isavirus
water
Prevention of influenzaviruses
vaccines
Isavirus clinical signs
pale gills, bloated abdomen, bleeding, swimming closer to the surface
Diagnosis of Orthomyxoviridae
cell culture or inside egg elisa pcr immunofluorescence haemagglutination tet
