Objectives:

The viral aetiology of acute lower respiratory infections (ALRIs) in hospitalised children under 3 years of age was studied.

Methods:

During the winter seasons from 1998 to 2003, 1847 children with ALRIs were tested for the determination of the responsible aetiologic viral agent. Nasopharyngeal aspirates (NPAs) were analysed for the common respiratory viruses antigen detection (RSV, influenza A (IA) and B (IB), parainfluenza (PIV) 1 + 2 and 3 and adenoviruses), using indirect immunofluorescence assay (IFA).

Results:

Viral agents were associated in 1032 of 1847 ALRIs cases (56%). The annual occurrence of viral ALRIs with the respiratory viruses detected is showed in Table 1:

RSV was identified in 933 NPA samples (90,4% of all viral diagnoses). Influenza A virus (5%), adenovirus (1.6%), influenza B (1.5%), PIV (1 + 2) (0.9%) and PIV3 (0.7%) accounted for 9.6% of the viral diagnoses. RSV was prevalent in children under 1 year of age (99%).

Conclusions:

RSV is the main aetiologic agent of viral ALRIs in young hospitalised children.