Family: Nairoviridae

Genus: Striwavirus

Distinguishing features

Sānxiá water strider virus 1 (SxWSV1) is the only classified striwavirus. SxWSV1 infects water striders (Gerridae) (Li et al., 2015, Shi et al., 2016).

Virion

Virions are unknown.

Nucleic acid

Striwaviruses have trisegmented negative-sense RNA genomes of 18.8 kb (small [S] segment: 2.2 kb; medium [M] segment: 4.2 kb; large [L] segment: 12.2 kb) (Li et al., 2015, Shi et al., 2016). Striwavirus genomic segments are expected to assume circular forms via non-covalent binding of complementary and conserved 3′- and 5′-terminal sequences.

Proteins

Based on sequence data only, striwaviruses likely express three structural proteins: nucleoprotein (N), glycoprotein precursor (GPC), and large protein (L).

Genome organization and replication

The S segment encodes N, the M segment encodes GPC, and the L segment encodes L (Figure 1 Striwavirus).

Figure 1 Striwavirus. Schematic representation of striwavirus genome organization. The 5′- and 3′-ends of each segment (S, M, and L) are, by analogy to other nairovirids, predicted to be complementary at their termini, likely promoting the formation of circular ribonucleoprotein complexes within the virion.

Biology

SxWSW1 infects water striders (Gerridae sp.) in China (Li et al., 2015, Shi et al., 2016). Replication-competent striwavirus isolates have not yet been obtained, and hence striwavirus biology remains to be elucidated.

Species demarcation criteria

The genus currently only includes a single species.