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Human Herpes Virus-6, HHV-7
· Associated with exanthem subitum and CNS disease
· HHV-7 specific for acute hemiplegia of childhood
· HHV-8 (Kaposi's sarcoma herpes virus, KSHV)
· Cause of Kaposi's sarcoma
HHV-6: Epidemiology and Transmission
· Antibody is present in 85% pregnant women, with active transport across placenta
· Newborn antibody levels decline in first 5 months of life (6%). The highest seroprevalence (86%) occurs at 1 year
· Lower mean titers are present after 40 years (60%)
· Increased prevalence IgM 6 months to 1 year of age
· Route of transmission: saliva most likely; no congenital or perinatal syndrome; not transmitted in breast milk
· Roseola (exanthem subitum, sixth disease)
· CNS: Febrile seizures, meningoencephalitis
· Nonspecific febrile illness
· Lymphadenopathy
· Hepatitis
· Intussusception
· Transplant patients: Pneumonitis, fever, mononucleosis-like
Exanthem subitum (ES) may be complicated by febrile (0.6-50%), bulging anterior fontanel, meningoencephalitis, hemiplegia, permanent paresis, mental retardation.
· Local production of antibody in CNS documented.
· HHV-6 gene sequence detected in brain tissue of child with ES and fatal fulminant hepatitis.
· Mechanism of association with febrile seizure: Reactivation of CNS HHV-6 by fever in patients with history of neurologic symptoms at time of acute ES.
· Possible etiologic role in multiple sclerosis HHV-6 virion syndrome proteins expressed in nuclei of oligodendrocytes in MS patients in association with MS Infectious Diseases Immunizations, HHV- 6/7, HSV, PARVOVIRUS B19, HEPATITIS C, ENTEROVIRUSES, RSV Respiratory Syncycial virus syndrome plaques
· First episode lesion: 50% HHV- 6/7, HSV, PARVOVIRUS B19, HEPATITIS C, ENTEROVIRUSES, RSV Respiratory Syncycial virus syndrome
· First episode asymptomatic: 33%
· Recurrent lesion: 4%
· Known past infection, no visible
lesions/prodrome 0.04%
· Prematurity
· Prolonged rupture of membranes
· Vaginal delivery
· Scalp electrode
· Vaccine not yet available
· Cultures during pregnancy
· Prenatal cultures are not predictive if neonatal infection
· Cultures are done at delivery in women with past history of herpes to facilitate early diagnosis of neonatal infection
· Recognition of active lesions during labor is usually followed by C-section delivery
· Antenatal acyclovir suppression is effective
· Maternal varicella
· Severe first episode HSV
· Maternal immunosuppression associated with HSV recurrence
· Treatment or suppression of new herpes lesion formation in preterm premature ROM
· Skin lesions (40%)
· DFA of scraping of base: Sensitivity >80%, few false positives