Clinical Background
Human herpesvirus 6 (HHV6), a member of the ß-herpesvirus subfamily, exists as 2 closely related variants, HHV6 A and HHV6 B.
Epidemiology
- Incidence - most children >2 years are seropositive
- Transmission
- Oral droplets
- Transfusion
- Organ transplantation
Organism
- DNA virus
- Isolated in 1986 from patients with AIDS and lymphoproliferative disease, the virus was originally named human B-lymphotropic virus (HBLV)
- Following the primary infection, the virus establishes a latent infection in lymphocytes and monocytes and may persist in various tissues with a low-level of replication
Clinical Presentation
- Primary infection with HHV6 produces a fever that may exceed 40°C, persisting for 3-5 days
- Primary infections in children often result in a fever followed by development of exanthem subitum, known as roseola infantum or sixth disease
- Rash develops on trunk and spreads to extremities
- Primary infections in adults, though rare, may involve:
- Infectious mononucleosis-like disease
- Fulminant hepatitis
- Atypical lymphocytosis
- Associated complications may include:
- Meningitis
- Meningoencephalitis
- Fulminant or chronic hepatitis
- Evidence suggests HHV6 may act as an opportunistic agent in:
- Immunodeficient patients undergoing bone marrow or organ transplants
- HIV-infected individuals by means of primary infection reactivation of a latent infection or a persistent infection
- In immunocompromised or immunosuppressed patients
- Symptoms -- Fever, skin rash, organ disease or rejection, encephalitis, encephalopathy, pneumonitis, hepatitis, bone marrow suppression and death
See Also
Diagnosis
Diagnosis
Differential Diagnosis
- Measles
- Rubella
- Viral/bacterial meningitis
- Viral illness
- Seizure disorder
Tests generally appear in the order most useful for common clinical situations
| Test name: Herpesvirus 6 (HHV6) (A&B), Quantitation by PCR
|
| ARUP #: 0060071 |
| Methodology: Polymerase Chain Reaction
|
| Use: Quantify Herpesvirus 6 in CSF, plasma and serum for determining treatment |
| Limitations: A negative result does not rule out the presence of HHV6 in concentrations below the detection level of the assay |
| Follow-up:
|
Additional Tests Available
| Test name: Herpesvirus 6 (HHV-6) Antibody, IgG
|
| ARUP #: 0065288 |
| Methodology: Enzyme-Linked Immunosorbent Assay
|
| Comments: |
References
Guidelines
Evidence based clinical practice guideline for fever of uncertain source in children 2 to 36 months of age. Cincinnati Children's Hospital Medical Center - Hospital/Medical Center. 2000 Feb (revised 2003 Oct 27). 12 pages. NGC:003783Evidence based clinical practice guideline for fever of uncertain source in infants 60 days of age or less. Cincinnati Children's Hospital Medical Center - Hospital/Medical Center. 1998 Sep 10 (revised 2003 Jun). 12 pages. NGC:003166 General References
Clark DA, Griffiths PD. Human herpesvirus 6: relevance of infection in the immunocompromised host. Br J Haematol.
2003;
120(
3):
384-395.
Fotheringham J, Jacobson S. Human herpesvirus 6 and multiple sclerosis: potential mechanisms for virus-induced disease. Herpes.
2005;
12(
1):
4-9.
Krueger GR, Ablashi DV. Human herpesvirus-6: a short review of its biological behavior. Intervirology.
2003;
46(
5):
257-269.
Ward KN. Human herpesviruses-6 and -7 infections. Curr Opin Infect Dis.
2005;
18(
3):
247-252.
Ward KN. The natural history and laboratory diagnosis of human herpesviruses-6 and -7 infections in the immunocompetent. J Clin Virol.
2005;
32(
3):
183-193.
Zerr DM. Human herpesvirus 6: a clinical update. Herpes.
2006;
13(
1):
20-24.
References from the ARUP Institute for Clinical and Experimental Pathology Research®
Herrmann MG, Durtschi JD, Bromley LK, Wittwer CT, Voelkerding KV. Amplicon DNA melting analysis for mutation scanning and genotyping: cross-platform comparison of instruments and dyes. Clin Chem.
2006;
52(
3):
494-503.
Hymas W, Stevenson J, Taggart EW, Hillyard D. Use of lyophilized standards for the calibration of a newly developed real time PCR assay for human herpes type six (HHV6) variants A and B. J Virol Methods.
2005;
128(
1-2):
143-150.
Rentz AC, Stevenson J, Hymas W, Hillyard D, Stoddard GJ, Taggart EW, Byington CL. Human herpesvirus 6 in the newborn intensive care unit. Eur J Clin Microbiol Infect Dis.
2007;
26(
4):
297-299.
Medical Reviewers
Hillyard, David R., M.D. Medical Director, Molecular Infectious Diseases at ARUP Laboratories; Associate Professor, Pathology, University of Utah
Comprehensive Review: November 2007
Last Update: November 2007
