Family: Kolmioviridae

Genus: Thurisazvirus

Distinguishing features

Tome’s spiny-rat virus 1 (TSRV1; previously referred to as RDeV) (Paraskevopoulou et al., 2020) was the first thurisazvirus to be classified (in the species Thurisazvirus myis), followed by bat deltavirus isolates LMA6, CAJ1, and AYA11 (Bergner et al., 2021) (members of the species Thurisazvirus desmodi). Thurisazviruses infect echimyid rodents and phyllostomid bats. TSRV1 replicates autonomously in vitro in HuH7 cells (Paraskevopoulou et al., 2020).

Virion

Virions are unknown.

Nucleic acid

Thurisazviruses have non-segmented, covalently-closed, circular negative-sense RNA (cccRNA) genomes of about 1.7 kb with 55.2% GC content (Paraskevopoulou et al., 2020).

Proteins

Thurisazviruses are predicted to express one delta antigen (DAg)-like protein of 196 amino-acid residues (Paraskevopoulou et al., 2020).

Biology

TSRV1 was discovered in Tome’s spiny-rats (echimyid Proechimys semispinosus (Tomes, 1860)) sampled in Panama (Paraskevopoulou et al., 2020). Bat deltavirus isolates LMA6, CAJ1, and AYA11 were discovered in phyllostomid bats in Peru (Bergner et al., 2021).

Species demarcation criteria

The genus currently includes two species. Members of the same species have a minimum of 80 % nt genome and 70 % S-DAg aa identity and form a monophyletic cluster in phylogenetic analyses.