Human Herpesviruses 6 and 7 (HHV6 and HHV7)
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Viruses - DNA Viruses
- Herpesvirus Overview
- Herpes Simplex Virus 1 (HSV1)
- Herpes Simplex Virus 2 (HSV2)
- Varicella-Zoster Virus (HHV3)
- Epstein-Barr Virus (HHV4)
- Cytomegalovirus (HHV5)
- Human Herpesviruses 6 and 7 (HHV6 and HHV7)
- Human Herpesviruses 8 (HHV8)
- Poxvirus
- Hepadnavirus
- Adenovirus
- Papillomavirus (HPV)
- Polyomavirus
- Parvovirus
Key Points
- Human herpesviruses 6 (HHV-6) and 7 (HHV-7)
- Characteristics
- Members of Herpesvirus family
- Enveloped DNA virus with double-stranded, linear DNA
- Herpesviruses are unique in that they get their envelope by budding from nuclear membrane of host cell
- Enveloped DNA virus with double-stranded, linear DNA
- HHV-7 shares 90% DNA homology with HHV-6
- Members of Herpesvirus family
- Transmission
- Saliva
- From mother to infant
- Salivary glands may be a latent reservoir
- Perinatal transmission is also possible
- Saliva
- Pathogenesis
- Virus replicates in many cells (macrophages, T-cells, salivary glands, neurons)
- Induces production of cytokines (TNF, IL-1, IFN-gamma)
- May cause latent infection (like other herpesviruses)
- Latent in lymphocytes and monocytes
- May reactivate in immunocompromised hosts
- Virus replicates in many cells (macrophages, T-cells, salivary glands, neurons)
- Clinical significance
- Roseola infantum
- Also known as exanthem subitum and sixth disease
- Affects babies (7-13 months old)
- High fever for 3-5 days
- Temperatures may exceed 40°C (104°F)
- Thought to result from viral replication and massive induction of fever-inducing cytokines
- Followed by macular/maculopapular rash
- starts on neck/trunk, spreads outwards to face/extremities
- Roseola infantum
- Diagnosis
- Diagnosis is clinical; labs are rarely useful
- Treatment
- Disease is usually self-limited
- Supportive care
- Disease is usually self-limited
- Characteristics