''Human betaherpesvirus 6B'' (HHV-6B) is a species of virus in the genus ''

Roseolovirus ''Roseolovirus'' is a genus of viruses in the order ''Herpesvirales'', in the family ''Herpesviridae'', in the subfamily ''Betaherpesvirinae''. There are currently six species in this genus. Diseases associated with this genus include: HHV-6: si ...

'', subfamily ''

Betaherpesvirinae ''Betaherpesvirinae'' is a subfamily of viruses in the order ''Herpesvirales'' and in the family ''Herpesviridae''. Mammals serve as natural hosts. There are 26 species in this subfamily, divided among 5 genera. Diseases associated with this sub ...

'', family ''

Herpesviridae ''Herpesviridae'' is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word ''ἕρπειν ...

'', and order ''

Herpesvirales The ''Herpesvirales'' is an order of dsDNA viruses (Baltimore group I) with animal hosts, characterised by a common morphology consisting of an icosahedral capsid enclosed in a glycoprotein-containing lipid envelope. Common infections in humans c ...

''.

Taxonomy

In 1992 the two variants were recognised within

Human herpesvirus 6 Human herpesvirus 6 (HHV-6) is the common collective name for ''human betaherpesvirus 6A'' (HHV-6A) and ''human betaherpesvirus 6B'' (HHV-6B). These closely related viruses are two of the nine known herpesviruses that have humans as their primar ...

on the basis of differing restriction endonuclease cleavages, monoclonal antibody reactions, and growth patterns. In 2012 these two variants were officially recognised as distinct species by the

International Committee on Taxonomy of Viruses The International Committee on Taxonomy of Viruses (ICTV) authorizes and organizes the taxonomic classification of and the nomenclatures for viruses. The ICTV has developed a universal taxonomic scheme for viruses, and thus has the means to app ...

and named ''Human betaherpesvirus 6A'' and ''Human betaherpesvirus 6B''. Despite now being recognised as

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

, the name Human herpesvirus 6 still sees usage in clinical contexts.

Pathology

''Human betaherpesvirus 6B'' affects humans. Primary infection with this virus is the cause of the common childhood illness

exanthema subitum Roseola, also known as sixth disease, is an infectious disease caused by certain types of human herpes viruses. Most infections occur before the age of three. Symptoms vary from absent to the classic presentation of a fever of rapid onset follo ...

(also known as roseola infantum or sixth disease). Additionally, reactivation is common in transplant recipients, which can cause several clinical manifestations such as

encephalitis Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...

, bone marrow suppression, and

pneumonitis Pneumonitis describes general inflammation of lung tissue. Possible causative agents include radiation therapy of the chest, exposure to medications used during chemo-therapy, the inhalation of debris (e.g., animal dander), aspiration, herbicides ...

References

{{Taxonbar, from=Q24808741 Betaherpesvirinae