Okavirus is a genus of viruses in the order Nidovirales, in the family Roniviridae. Okaviruses infect crustaceans, mostly prawns. There is currently only one species in this genus: the type species Gill-associated virus. Diseases associated with this genus include: GAV: reddening, biofouling with exoparasites, emaciation, massive mortality; YHV: yellow head, arrest of feeding. massive mortality. The name is derived from the 'Oka' or lymphoid organ in which the viruses are commonly detected and in which pathology occurs during acute infections. Lymphoid organs are anatomical structures common to penaeid shrimp.
Entry into the host cell is achieved by attachment to host receptors, which mediates endocytosis. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. Crustaceans and mostly prawns serve as the natural host. Transmission routes are ingestion.
^Cowley JA, Dimmock CM, Spann KM, Walker PJ (2000) Gill-associated virus of Penaeus monodon prawns: an invertebrate virus with ORF1a and ORF1b genes related to arteri- and coronaviruses. J Gen Virol 81(Pt 6):1473–1484
^Sittidilokratna N, Dangtip S, Cowley JA, Walker PJ (2008) RNA transcription analysis and completion of the genome sequence of yellow head nidovirus. Virus Res 136(1–2):157–165