Summary

ratory syncytial virus (RSV) infections in our country are not abundant. The aim of this study was to deter-mine the frequency and general epidemiological properties of RSV in acute bronchiolitis (AB) and to investigate the accuracy and cost-effectivity of vari-ous diagnostic methods. A total of 76 children younger than 2 years of age who had the diagnosis of AB in the outpatient clinic or the emergency room were included. The criteria for the clinical diagnosis of viral AB were wheezing and sibilant rhonchi following a nonspecific viral upper respiratory infection of a few days along with hyper-aeration on the chest X-ray. Patients with evidence of bacterial infection were excluded. The nasopharyngeal secretions (NS) and sera of the patients were obtained and stored at-20°C to be subsequently tested for RSV antigen (Test Pack?, Abbott) in the NS and anti-RSV-IgG (two samples 14 days apart) as well as anti-RSV IgM antibodies in sera (ELISA, Euroimmune?). The assays were run simulta-neously on the same batch. Of the 76 patients with AB, 73.6 % were male and 26.4 % were female. Their mean age was 9.4±5.3 months (X±SD; range: 2-24). The age distribution was 2-6 months in 26.3 % patients, 7-12 months in 52.6% patients, and 13-24 months in 21.1 % patients. RSV antigen in NS was positive in 36 (47.3%) patients, 4 of whom (5.2%) had anti-RSV-IgM in sera as well. Anti-RSV IgM was detected in an additional 3 patients whose NS were antigen-negative adding up to 39 (51.2%) patients with AB. Four patients tested positive for anti-RSV IgM only one of whom had a positive anti-gen in the NS. Out of 16 patients who had anti-RSV IgG concentration and were assayed twice after 14 days, 2 (12.5%) patients had increased concentrations of anti-RSV IgG in the second sample. Male/female ratio was 31/8 in RSV positive patients, and 25/12 in RSV negative patients (p>0.05). The ag