Objectives:

To define the frequency of positive anti-adenoviral IgG and IgA antibodies in children hospitalised during the current year (2003) in our children's hospital.

Methods:

A total of 355 children younger than 14 years of age were examined, all of whom had been treated as inpatients for symptoms of viral, febrile illness.

Anti-adenoviral IgG and IgA antibodies were assessed by conventional enzyme-linked immunosorbent assay (ELISA). The major antigenic determinant that was used, is common for all adenoviral subtypes that produce illness in humans. IgG quantification was performed using the single-cut-off method, which provides high accuracy and reproducibility of results. High IgG and positive IgA antibody titres were considered to be indicative of acute infection (early phase). The finding of a low IgG antibody titre alone was interpreted as a normal immune response to recurrent, symptomatic or clinically silent infection by various adenoviral subtypes.

Results:

Of a total of 355 sera examined, 62 (17.4%) were found to be positive for anti-adenoviral antibodies. The 62 patients with positive antibody tests against adenoviruses had been mainly treated for upper (pharyngitis, tonsillitis) or lower (bronchiolitis, pneumonia) respiratory-tract infections. 45% of all patients (355) were found to be positive for IgG antibodies only, a finding suggesting past infection, whether symptomatic or clinically silent.

Conclusion:

Adenoviruses constitute a significant causative agent of respiratory infections in children, with a higher incidence during spring time (54% of all cases examined).