CHILDHOOD INFECTIOUS MONONUCLEOSIS NOT ASSOCIATED WITH EPSTEIN-BARR VIRUS

Non-Epstein-Barr Virus (EBV) induced infectious mononucleosis (IM) has not been adequately studied in children. In a prospective evaluation of 171 children with an illness characterized by clinical and hematologic findings for IM, 19 (11%) children had their episode unassociated with an acute EBV infection. The majority of children with non-EBV IM were <4 years old, 11 (58%), and males, 11 (58%). The spectrum of clinical manifestations in general were similar to that reported for EBV-IM in children except for a decreased rate of exudative tonsillitis in the non-EBV group, 5 (26%). Transient respiratory or hematologic complications developed in 2 children. Liver transaminases were elevated acutely and transiently in 6/10 children tested. Typical heterophil antibody responses were not detected. EBV testing indicated that 6 children had experienced this infection in the distant past; the infection in two others was of inconclusive onset. A suspected etiology was identified in 5 children: 3 had significant IgG antibody titer rises to cytomegalovirus (2 of these had the virus isolated from the urine) and 2 others had significant titer rises to Toxoplasma gondii. Children with non-EBV IM tended to be younger than that reported with EBV-IM. The non-EBV IM subgroup with suspected etiology appeared to be a major contributor to the low frequency of exudative tonsillitis. Reactivation of an EBV-carrier state provoked by the intervening etiologic agent was not documented as has been reported in adults. The majority of non-EBV IM episodes in children remains of unknown etiology.