Genus: Striavirus


Genus: Striavirus

Distinguishing features

Xīlǎng virus (XILV) is the only currently classified striavirus. Like thamnoviruses, but unlike cuevaviruses, ebolaviruses, and marburgviruses, striaviruses appear to infect fish (Shi et al., 2018). Notably, striaviruses do not encode obvious surface glycoproteins.

Virion

Morphology

Not reported.

Physicochemical and physical properties

Not reported. 

Nucleic acid

Virions are assumed to contain one or several copies of linear negative-sense ssRNA genomes that are encapsidated independently.

Proteins

Striaviruses likely express at least 10 proteins, of which four (NP, VP40, VP30, and L) are homologs of proteins expressed by cuevaviruses, ebolaviruses, and marburgviruses and two (NP and L) are homologs of proteins expressed by thamnoviruses. The second most abundant structural protein in virions is assumed to be the nucleoprotein (NP), which encapsidates the striavirus genome. The least abundant protein is assumed to be the RNA-dependent RNA polymerase (L), which mediates striavirus genome replication and transcription (Shi et al., 2018).

Lipids

Not reported.

Carbohydrates

Not reported.

Genome organization and replication

The striavirus genome has the gene order: 3′-NP-U1-VP40-U2-U3-U4-VP30-U5-U6-L-5′ with U denoting genes expressing proteins of unknown function (Figure 1.Striavirus). The undetermined extragenic sequences at the extreme 3′ (leader) and 5′ (trailer) ends of the genome are assumed to be conserved and partially complementary. Genes are flanked by unique conserved transcriptional initiation and termination (polyadenylation) sites. All striavirus genes overlap.

Figure 1.Striavirus. Schematic representation of the filovirus genome organization. Genomes are drawn to scale. Courtesy of Jiro Wada, IRF-Frederick, Fort Detrick, MD, USA.

The replication strategy of striaviruses remains to be studied.  

Antigenicity

Not reported.

Biology

Striaviruses were discovered in 2011 by next generation sequencing of samples taken from striated frogfish (Antennarius striatus Shaw, 1794) captured by fishing trawlers in the East China Sea (Shi et al., 2018).

Species demarcation criteria

The genus currently includes only a single species. 

Member species

SpeciesVirus name(s)Exemplar isolateExemplar accession numberExemplar RefSeq numberAvailable sequenceOther isolatesOther isolate accession numbersVirus abbreviationIsolate abbreviation
Xilang striavirusXīlǎng virus; Wēnlǐng frogfish filovirusXīlǎng virus/A.striatus-wt/CHN/2018/XYHYS28627MG599980Complete coding genomeXILV

Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.

Derivation of names

Striavirus: from Antennarius striatus, the fish species to which the presumed host of XILV, striated frogfish, has been assigned (Shi et al., 2018).