Abstract
An institutional epidemic of mumps was seen among the infants under 2 years of age. Epidemiological, clinical and serological studies on the epidemic were carried out in 47 infants of the nursery. Furthermore by utilizing fluorescent antibody tests the influence of transplacental maternal antibodies on mumps infection of infants was studied. The significance of fluorescent antibody tests in mumps infection was discussed.
The results obtained were as follows:
1) An epidemic of mumps was found to occur even in infants around 1 year of age, when the proportion of susceptibles in the population was high and when they were in close contact with each other.
2) Even the small amount of transplacental maternal antibodies, which were undetectable by hemagglutination inhibiting or neutralizing tests but detectable only by fluorescent antibody tests, might protect mumps infection in infancy.
3) Fluorescent antibody tests were considered to be useful to determine whether the detected antibodies were due to natural mumps infection or of maternal origin: IgM mumps fluorescent antibody was specifically detected in sera of those who received recent infection of mumps.
