CONGENITAL CYTOMEGALOVIRUS INFECTION: CONSECUTIVE OCCURRENCE DUE TO VIRUSES WITH SIMILAR ANTIGENIC COMPOSITIONS

The occurrence of congenital cytomegalovirus infection in two siblings born three years apart is reported. Based on clinical and immunologic findings, the older child seems to have been exposed to a strong and prolonged antigenic stimulus, while the younger was probably affected by a reduced or modified load. Simultaneous complement-fixing (CF) and neutralizing (NT) antibody determinations done in infants and maternal sera suggest that the viruses isolated from both cases, if not identical, are antigenically quite similar and, furthermore, they are very close to AD-169 and Davis prototypes. Therefore, although the mother showed a significant antibody rise and became viuric during the second pregnancy, it is very unlikley that a new primary infection with an heterologous strain occurred, and we suggest endogenous reactivation or reinfection with the homologous virus. The implications of this finding with respect to counseling parents of a congenitally infected child about future pregnancies are discussed.