<unk>  <unk>  is the common collective name for<unk>  betaherpesvirus<unk> A <unk> A) and<unk>  betaherpesvirus<unk> B <unk> B). These closely related viruses are two of the nine known<unk>  herpesviruses, herpesviruses that have<unk> s as their primary host.<unk> A and<unk> B are double-stranded DNA viruses within the Betaherpesvirinae subfamily and of the genus Roseolovirus.<unk> A and<unk> B infect almost all of the<unk>  populations that have been tested.<unk> A has been described as more neurovirulent, and as such is more frequently found in patients with neuroinflammatory diseases such as multiple sclerosis.<unk>  (and HHV-7) levels in the brain are also elevated in people with Alzheimer's disease.<unk> B primary infection is the cause of the common childhood illness exanthema subitum (also known as roseola infantum or sixth disease). It is passed on from child to child. It is uncommon for adults to contract this disease as most people have had it by kindergarten, and once contracted, immunity arises and prevents future reinfection. Additionally,<unk> B reactivation is common in transplant recipients, which can cause several clinical manifestations such as encephalitis, bone marrow suppression, and pneumonitis. A variety of tests are used in the detection of<unk> , some of which do not differentiate the two species.
Human herpesvirus 6
Human betaherpesvirus 5
Human betaherpesvirus 7
Human T-lymphotropic virus 2
Human T-lymphotropic virus 1
Trichodysplasia spinulosa polyomavirus
Molluscum contagiosum virus
Epstein–Barr virus