Microbiology · Human herpesviruses
Human herpesviruses 6 and 7 !
- Virus
- Enveloped
- Exam priority: medium
Herpesviruses that cause roseola in infants: several days of high fever and, as it breaks, a pink rash.
Updated 2026-11-01
Also called: HHV-6, HHV-7, roseola, exanthem subitum, sixth disease
At a glance
- Shape
- Icosahedral with tegument and envelope
- Genome
- Linear double-stranded DNA
- Envelope
- Enveloped
- Family
- Herpesviridae (betaherpesvirus, genus Roseolovirus)
- Size
- About 150 to 200 nm
Morphology
- Typical herpesvirus structure
- Infect mainly CD4 T cells
Transmission
- Saliva from adults and children who shed the virus
- Nearly all children are infected in the first years of life
Reservoir: Humans
Isolation precautions
What the care team adds to standard precautions.
- Standard
Virulence factors
- Persists after infection; replicates in CD4 T cells, and the main latency cell is still debated (monocytes are proposed)
- Reactivation in transplant recipients, with fever, bone marrow suppression or encephalitis
Diseases it causes
- Roseola (exanthem subitum) Roseola infantum (exanthem subitum) →
- Febrile seizures and, rarely, encephalitis
Clinical picture
- Infants from 6 months to 2 years: sudden high fever for several days while the child looks fairly well
- As the fever breaks, a pink maculopapular rash appears on the trunk
- High fever can trigger febrile seizures
Diagnosis
- Clinical diagnosis from the sequence of fever then rash
- PCR or serology in atypical cases or in transplant recipients
Treatment
Supportive care with antipyretics for roseola. In immunocompromised patients with severe disease, ganciclovir or foscarnet have been used.
Drug class only; doses and regimens are set by the clinician from the current guideline.
Prevention
- No vaccine
- Standard precautions
Test yourself
Think of the answer, then tap the question to see it.
When does the rash appear in roseola?
When the high fever of several days breaks, typically in an infant who looked fairly well.
Which neurologic complication is common in roseola?
Febrile seizures from the sudden high fever.
Which viruses cause exanthem subitum?
Human herpesvirus 6 (mainly 6B) and, less often, human herpesvirus 7.
Related
Related conditions
← Back to the group: Human herpesviruses
Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Roseola (MedlinePlus (NLM), 2024); Appendix A: Type and Duration of Precautions Recommended for Selected Infections and Conditions (CDC, 2024).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.