Serological diagnosis of respiratory viral infections. A five-year study of hospitalised patients.

The results of a five-year study of paired sera from 410 hospitalised patients-mainly children-with respiratory illness are reported. Samples were divided into groups based on clinical diagnosis. The data of each group were analysed in relation to patient age (under or over 1 year of age). The percentage of positive serological diagnoses ranged from 29.4% in the respiratory viral illness group to 46.2% in the bronchiolitis group. Each group showed a prevalent serological diagnosis. Respiratory viral illness patients over 1 year were diagnosed mainly with Influenza virus infection (73.8% positive diagnosis), pharyngotonsillitis patients with Adenovirus infection (72.2%), laryngitis patients with Parainfluenza virus infection (100%), pneumonia patients with Mycoplasma pneumoniae infection (56.7%), and bronchiolitis patients with Respiratory Syncytial virus infection (100%). The serological diagnosis patterns of each group or subgroup were statistically significant with respect to the other groups (chi 2 or Fisher exact tests). Unlike previous reports, none of the patients under 1 year in our study was diagnosed with Influenza virus infection or Parainfluenza virus type 3. Conversely, Respiratory Syncytial virus infection data were in line with previous reports, being the most frequently diagnosed infection in the bronchiolitis group and in the subgroups of patients under 1 year of age. The present report provides new information on patterns of respiratory infections.