Bunyaviridae
2011; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-12-384684-6.00059-8
Tópico(s)Vector-Borne Animal Diseases
ResumoPublisher SummaryThis chapter focuses on Bunyaviridae family whose member genera are Orthobunyavirus, Hantavirus, Nairovirus, Phlebovirus, and Tospovirus. The morphological properties vary among viruses in each of the five genera, however, virions generally are spherical or pleomorphic, 80–120 nm in diameter, and display surface glycoprotein projections of 5–10 nm which are embedded in a lipid bilayered envelope approximately 5 nm thick. The virion envelopes are usually derived from cellular Golgi membranes, or on occasion, from cell surface membranes. The terminal nucleotides of each genome RNA segment are base-paired forming noncovalently closed, circular RNAs (and ribonucleocapsids) and the terminal sequences of genome segments are conserved among viruses in each genus but are different from those of viruses in other genera. Nonstructural proteins are expressed from the S segments of some bunyaviruses, phleboviruses, tospoviruses and some hantaviruses, and from the M segments of bunyaviruses, nairoviruses, tospoviruses and some phleboviruses. The virions contain 20–30% lipids by weight, which are derived from the membranes where viruses mature and include phopholipids, sterols, fatty acids and glycolipids. They contain 2–7% carbohydrate by weight and asparagine-linked sugars on the Gn and Gc proteins are largely of the high mannose type when viruses are grown in vertebrate cells. Viruses in the genera Orthobunyavirus, Nairovirus and Phlebovirus are capable of alternately replicating in vertebrates and arthropods, and generally are cytolytic for their vertebrate hosts, but cause little or no cytopathogenicity in their invertebrate hosts.
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