The virus exanthema subitum (human herpesvirus 6 HHV-6, Human herpes reseovirus 9) exists in two variants, HHV-6A and HHV-6B, differing somewhat genetically, biologically and antigenically. The primary infection of HHV-6 frequently occurs as a vague illness with a fairly high fever, sometimes accompanied by convulsions. In older infants and toddlers up to one-fifth of the fever is of a roseolovirus origin. A rash appears in only about 20% of children, that is exanthema subitum or roseola infantum, also known as the sixth exanthematic illnesss. Hepatitis or atypical lymphocytosis are rarely present . If a reactivation has been reported, and in otherwise normal people (pregnancy after admission to the intensive care unit for other serious diseases) presented without symptoms. The reactivation of HHV-6B, however, occurs in up to half of transplant recipients. It presents again as a febrile illness, but also encephalitis, pneumonia, hepatitis and symptoms of bone marrow suppression and deterioration of a CMV infection. Strikingly there are also mental status changes - from confusion to even coma. HHV-6 also contributes to immune suppression caused by HIV co-infection and induces the production of cytokines.


  • Method:
    Amplification and detection of the viral genome by means of nested PCR (minimum sensitivity 5 copies per reaction) and reverse hybridization (minimum sensitivity 5 copies per reaction)
  • Material:
    • whole blood (EDTA tube - transport to the laboratory within 24 hours from extracting it in room temperature)
    • plasma (after centrifugation of whole blood in EDTA tube at 1200xg for 10 min. to 7 days may be stored at 2/8 °C, longer at -18 / -22 °C)
    • cerebrospinal fluid, urine, biopsy (-18 / -22 °C)


  1. Votava M. a kol.: Lékařská mikrobiologie speciální, Neptun, 2003.
  2. Leibovitch EC, Brunetto GS, Caruso B, Fenton K, Ohayon J, Reich DS, Jacobson S. Coinfection of human herpesviruses 6A (HHV-6A) and HHV-6B as demonstrated by novel digital droplet PCR assay. PLoS One. 2014 Mar 24;9(3).
  3. Bressollette-Bodin C, Nguyen TV, Illiaquer M, Besse B, Peltier C, Chevallier P, Imbert-Marcille BM. Quantification of two viral transcripts by real time PCR to investigate human herpesvirus type 6 active infection. J Clin Virol. 2014 Feb;59(2).