Notes on Family: Orthomyxoviridae
enveloped spheres or pleomorphic
This family contains a single genus of viruses that have pleomorphic, enveloped, particles with club-shaped projections and have a bipartite ambisense RNA genome.
Virions spherical or pleomorphic, enveloped, 80-120 nm in diameter, with projections 4-6 nm in diameter and 10-14 nm long.
Multipartite (6-8 segments) single-stranded negative sense RNA totalling 10-15 kb. There is no genome-linked protein (VPg) at the 5'-termini nor 3'-polyA tails. The larger genome segments each encode a single protein while the smaller segments often encode additional proteins from spliced or bicistronic mRNAs.
Genera in the Family
- Influenzavirus A: 8 segments, transmitted by aerosols to vertebrates; segment 6 encodes a neuraminidase
- Influenzavirus B: 8 segments, transmitted by aerosols to vertebrates; segment 6 encodes a neuraminidase and a membrane protein
- Influenzavirus C: 7 segments, transmitted by aerosols to vertebrates
- Isavirus: 8 segments, infecting fish
- Quaranjavirus: 6 segments, transmitted by ticks to vertebrates but not closely related to thogotoviruses
- Thogotovirus: 6 or 7 segments, transmitted by ticks to vertebrates