Discovery of an orthoreovirus in the aborted fetus of a Steller sea lion (Eumetopias jubatus).

An aborted mid-gestational male Steller sea lion fetus with an attached placenta was recovered on the floor of an open floating capture trap located off Norris Rock near Denman Island, British Columbia. Viral culture of the placenta demonstrated cytopathic effect. Although no specific signal was obtained in microarray experiments using RNA obtained from viral culture, elution and sequence analysis revealed the presence of a reovirus. Complete genome pyrosequencing led to the identification of an orthoreovirus that we have tentatively named Steller sea lion reovirus (SSRV). Phylogenetic analysis revealed similarities between SSRV and orthoreoviruses of birds, bats and other mammals that suggests potential for interspecies transmission.

Genomic and phylogenetic characterization of Leanyer virus, a novel orthobunyavirus isolated in northern Australia.

Leanyer virus (LEAV), currently classified as a member of the genus Orthobunyavirus, in the family Bunyaviridae, was originally isolated from a pool of Anopheles meraukensis mosquitoes, collected at Leanyer, Northern Territory, Australia in 1974. When it failed to react in serological tests with antisera from other known viruses, full-length genomic sequencing was pursued to determine the relationship of LEAV to other orthobunyavirus species. Genetic and serological characterization confirmed its antigenic distance from other orthobunyaviruses, including to its closest genetic neighbours, the Simbu group viruses, suggesting that it may represent a new antigenic complex.

Heart and skeletal muscle inflammation of farmed salmon is associated with infection with a novel reovirus.

Atlantic salmon (Salmo salar L.) mariculture has been associated with epidemics of infectious diseases that threaten not only local production, but also wild fish coming into close proximity to marine pens and fish escaping from them. Heart and skeletal muscle inflammation (HSMI) is a frequently fatal disease of farmed Atlantic salmon. First recognized in one farm in Norway in 1999, HSMI was subsequently implicated in outbreaks in other farms in Norway and the United Kingdom. Although pathology and disease transmission studies indicated an infectious basis, efforts to identify an agent were unsuccessful. Here we provide evidence that HSMI is associated with infection with piscine reovirus (PRV). PRV is a novel reovirus identified by unbiased high throughput DNA sequencing and a bioinformatics program focused on nucleotide frequency as well as sequence alignment and motif analyses. Formal implication of PRV in HSMI will require isolation in cell culture and fulfillment of Koch's postulates, or prevention or modification of disease through use of specific drugs or vaccines. Nonetheless, as our data indicate that a causal relationship is plausible, measures must be taken to control PRV not only because it threatens domestic salmon production but also due to the potential for transmission to wild salmon populations.