Investigation of viral etiology in lower respiratory tract infections in children by indirect immunofluorescence method

Abstract

In this study, to investigate the viral etiology of lower respiratory tract infections (LRTI) in our region, the nasopharyngeal aspirate (NPA) samples of 124 pediatric patients (age range: 0-5 years) with LRTI were prospectively collected and studied by indirect immunofluorescence assay (IFA) with the use of monoclonal antibodies against Respiratory Syncytial Virus (RSV), Parainfluenza virus type 1, 2, 3, Influenza virus type A and B, Coronavirus and Adenovirus antigens. Of 124 NPA samples, 35 (28.2%) were found positive by means of viral antigens and RSV was the most common etiologic agent with a rate of 40% (14/35), followed by Parainfluenza virus types (10/35, 28.6%), Influenza B virus (4/35, 11.4%), Coronavirus (3/35, 8.6%), Influenza A virus (2/35, 5.7%) and Adenovirus (2/35, 5.7%). Laboratory diagnosis of RSV infections which are very common in winter season, depends on the isolation from tissue cultures that is known to be the gold standard, is time consuming and expensive. Therefore, to search the RSV antigens routinely by IFA method in NPA samples will be more appropriate for rapid diagnosis.