Orthomyxoviridae Flashcards
What viruses are included in Influenza A?
human, equine, swine and domestic poultry viruses
What viruses are included in Influenza B?
human viruses
What viruses are included in Influenxa C?
human and swine viruses that rarely cause dz
What is the only member of genus Isavirus?
infectious salmon anemia virus
Tick borne viruses are in which genus?
Thogotovirus
How are orthomyxoviruses classified?
based on type of HA and N
How are influenza viruses named?
type/host/geographical origin/strain #/year of isolation/HN
e.g. A/equine/Miami/1/1963 (H3N8)
T/F virions are pleomorphic and non-segmented
F: they are segmented
T/F influenza F lack Neuraminidase
T
3 functions of HA
receptor binding, membrane fusion, receptor cleavage
genome composed of:
6-8 segments of linear, negative sense ssRNA
Where does uncoating occur?
cytoplasm
Where does viral protein synthesis occur?
cytoplasm using cell machinery
How is the virus transmitted in aquatic birds
shed in feces -> fecal oral
How is the virus transmitted in poultry?
ingestion and inhalation
How if the virus transmitted in mammals?
aerosol, dropelets and fomites
T/F genetic drift and shift occur in orthomyxoviruses?
T
Where does equine influenza replicate?
epithelial cells of upper and lower respiratory tracts
symptoms of equine influenza
fever, nasal discharge, dry cough, mucopurulent discharge in late stages
T/F animals are no longer infectious when clinical signs disappear
F: remain infectious at least 5 days
What type of horses are susceptible to equine influenza?
race horses, breeding stock, show jumpers
T/F pigs can become co-infected with both avian and human strains of influenza
T: have human (SAa2,6Gal) and avian (SAa2,3gal) receptors
Where does swine influenza replicate?
upper respiratory tract
Is incubation of swine influenza long or short?
short
T/F swine influenza is always fatal
F: not if animals are kept warm and stress free
Are there vaccines for swine influenza?
Yes but don’t confer cross protection against new subtypes
