PRIMARY HUMAN-HERPESVIRUS-7 INFECTION - A COMPARISON OF HUMAN-HERPESVIRUS-7 AND HUMAN-HERPESVIRUS-6 INFECTIONS IN CHILDREN

To define the clinical and virologic characteristics of primary human herpesvirus 7 (HHV-7) infection and to compare these characteristics w ith those of primary human herpesvirus 6 (HHV-6) infection. Study desi gn: A prospective convenience sample study of 496 children less than o r equal to 3 years old. HHV-7 and HHV-6 infections were identified by viral isolation. Polymerase chain reaction and serology for HHV-7 and HHV-6 were performed. Clinical and laboratory characteristics of patie nts were obtained from medical records and follow-up interviews. Resul ts: Children with primary HHV-7 infection (n = 8) were identified and compared with children with primary HHV-6 infection (n = 29) detected during the same time period. All children were febrile (mean temperatu re 39.8 degrees C) with no difference in the degree of fever, frequenc y of rash, or gastrointestinal complications between the groups. The m edian age of children with primary HHV-7 infection was 26 months, sign ificantly older than that of children with primary HHV-6 infection (me dian, 9 months). Children with primary HHV-7 infection were also more likely than those with primary HHV-6 infection to have seizures associ ated with the illness (P = .004). Conclusion: Primary infection with H HV-7 can cause a highly febrile illness in childhood, complicated by s eizures. The serologic diagnosis of primary HHV-6 and HHV-7 infections may be confounded by cross-reacting antibodies.