Family: Chuviridae

Genus: Nigecruvirus

Distinguishing features

Nigecruviruses are primarily distinguished from viruses of other genera in the family based on nucleic acid sequence and organization differences (Di Paola et al., 2022). Members of the genus Nigecruvirus have L protein sequences that are >31% identical to each other.

Genome organization and replication

Nigecruviruses have nonsegmented circular genomes of 10.5–11.5 kb with three to four ORFs encoding a glycoprotein (GP), a large (L) protein with an RNA-directed RNA polymerase (RdRP) domain, a nucleoprotein (NP), and a protein of unknown function (Tokarz et al., 2018, Wu et al., 2020). The replication cycle of nigecruviruses remains to be elucidated.

Biology

Nigecruviruses have been associated with ixodidan arachnids and blattodean insects:

• blacklegged tick chuvirus 2 (BlTCV2) has been associated with deer ticks (ixodid Ixodes scapularis Say, 1821) in the USA (Tokarz et al., 2018); and
• Periplaneta americana mononega-like virus (PAmlV) has been associated with American cockroaches (blattid Periplaneta americana (Linnaeus, 1758)) in Germany (Wu et al., 2020).

Species demarcation criteria

Members of different species have amino-acid identities of complete L sequences of <90% (Di Paola et al., 2022).

Related, unclassified viruses

Virus names and virus abbreviations are not official ICTV designations.