Family: Chaacviridae (Interim Report)

This is a summary page created by the ICTV Report Editors using information from associated Taxonomic Proposals and the Master Species List.

Edited by: Mart Krupovic
Posted: October 2024, updated March 2025

Summary

The family Chaacviridae includes dsDNA viruses that infect anaerobic methanotrophic ANME-1 archaea (Table 1 Chaacviridae). The family Chaacviridae was established in 2023 (Master Species List #38).

Table 1 Chaacviridae. Characteristics of members of the family Chaacviridae.

Characteristic	Description
Example	Methanophagales virus PBV304 (OP548099), species Homochaacvirus pescaderoense, genus Homochaacvirus
Virion	Only known from metagenomic studies, predicted to have tailless icosahedral virions
Genome	Linear, dsDNA genomes of 10.2–10.8 kbp with inverted terminal repeats
Host range	Anaerobic methanotrophic ANME-1 archaea
Taxonomy	Realm Varidnaviria, kingdom Abadenavirae, phylum Produgelaviricota, class Belvinaviricetes, order Coyopavirales: 2 genera and 3 species

Figure 1 Chaacviridae. Genome organisation of Methanophagales virus PBV304, a member of the family Chaacviridae. Boxes indicate open reading frames as annotated on GenBank accession OP548099.

Figure 2 Chaacviridae. Taxonomy of the family Chaacviridae.

Derivation of names

Chaacviridae: from Chaac, the god of rain in Mayan mythology

Antichaacvirus: from the Greek anti, meaning “opposed”

Homochaacvirus: from the Greek homo, meaning “same”