Genus: Roseolovirus

Genus: Roseolovirus

Distinguishing features

The predicted amino acid sequences of members form a distinct lineage within the subfamily (Figure 1.Betaherpesvirinae).

Virion

See discussion under family description.

Genome organization and replication

Members have a class 1 genome architecture (Figure 2.Herpesviridae). Human herpesvirus 6A (HHV6A in the species Human betaherpesvirus 6A), human herpesvirus 6B (HHV6B in the species Human betaherpesvirus 6B) and human herpesvirus 7 (HHV7 in the species Human betaherpesvirus 7) infect humans and have telomere-like repeats bounding their genomes. HHV6A and HHV6B  exhibit genetic adaptations to tissue culture that are similar to, but less extensive than, those described for members of the genus Cytomegalovirus (Tweedy et al., 2017). HHV6A and HHV6B genomes integrated into the human germline have been sequenced (Tweedy et al., 2016).

Biology

Members have mammals as hosts. Those infecting humans are known to infect T lymphocytes productively, but porcine cytomegalovirus (in the species Suid betaherpesvirus 2) has been detected in swine pulmonary macrophages and tonsils. In humans, infection generally causes a mild fever in infants, with HHV6B dominant in the condition of roseola infantum (exanthem subitem), but in some cases infection can be severe and involve neurological disease.

Species demarcation criteria

See discussion under family description.

Member species

Exemplar isolate of the species
SpeciesVirus nameIsolateAccession numberRefSeq numberAvailable sequenceVirus Abbrev.
Human betaherpesvirus 7human betaherpesvirus 7; human herpesvirus 7RKAF037218NC_001716Complete genomeHuBHV7; HHV7
Human betaherpesvirus 6Ahuman betaherpesvirus 6A; human herpesvirus 6AU1102X83413NC_001664Complete genomeHuBHV6A; HHV6A
Human betaherpesvirus 6Bhuman betaherpesvirus 6B; human herpesvirus 6BZ29AF157706NC_000898Complete genomeHuBHV6B; HHV6B
Macacine betaherpesvirus 9macacine betaherpesvirus 9; Macaca nemestrina herpesvirus 7KU351741NC_030200Complete genomeMcBHV9; MneHV7
Murid betaherpesvirus 3murid betaherpesvirus 3; mouse thymic virusYOK1KY355735NC_033620Complete genomeMuBHV3; MTV
Suid betaherpesvirus 2suid betaherpesvirus 2; porcine cytomegalovirusBJ09KF017583NC_022233Complete genomeSuBHV2; PCMV

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