Human Herpesvirus 6 (Including Roseola) and 7

Human herpesvirus 6 and 7 comprise 3 distinct viral species, HHV-6B, HHV-6A, and HHV-7. Although many infections are asymptomatic, clinical manifestations of primary infection with human herpesvirus 6B (HHV-6B) include roseola (exanthem subitum) in approximately 20% of infected children as well as a nonspecific febrile illness without rash or localizing signs. Acute HHV-6B infection may be accompanied by cervical and characteristic postoccipital lymphadenopathy, gastrointestinal tract or respiratory tract signs, and inflamed tympanic membranes. Fever may be high (temperature >39.5°C [103.0°F]) and persist for 3 to 7 days. Approximately 20% of all emergency department visits for febrile children 6 through 12...