[Common viral etiologies of community acquired lower respiratory tract infections in young children and their relationship with long term complications].

Viral lower respiratory tract infections (LRTIs) and their late complications are important causes of morbidity and mortality in childhood. The aims of this study were the detection of viral agents that cause community-acquired LRTIs in young children and investigation of the relationship between viral etiology and bronchiolitis obliterans (BO) which is one of the late complications of LRTIs. A total of 151 children (86 male, 65 female; mean age: 2.9 +/- 1.9 years) who were diagnosed to have LRTIs between the period of 2002-2004, at Pediatric Allergy and Pulmonology Department of a University Hospital in Manisa (located in the Aegean region of Turkey) were included to the study. The presence of respiratory viruses [respiratory syncytial virus (RSV), influenza virus type A and B, parainfluenza virus types 1, 2 and 3, adenovirus] in the nasopharyngeal aspirate specimens collected from children have been searched by direct fluorescence antibody test (Biotrin, Ireland). Respiratory viruses were detected in 25.2% (38/151) of the patients with LRTIs, while this rate was 46.8% (22/47) for 2002 period, 13.3% (8/60) for 2003 period and 18.2% (8/44) for 2004 period. RSV and adenoviruses both detected with a frequency of 31.5% (n= 12/38); were the most common agents encountered, and followed by parainfluenza (10/38, 26.3%) and influenza (9/38, 23.6%) viruses. Postinfectious BO have been diagnosed in 7.3% (11/151) of the patients; seven in 2002, one in 2003 and three in 2004 periods. Viral etiology were present in all of the patients who developed BO in 2002, while viral infection was detected in one of the patients who developed BO in 2003-2004 periods. Adenoviruses were the most frequently detected agents (n= 5) in BO cases with viral etology (n= 8). Viral agents were found positive in 72.7% (8/11) and 21.4% (30/140) of the patients with and without BO development, respectively, and this difference was found statistically significant (p= 0.02). Besides, BO development was detected in 21.1% (8/38) and 2.6% (3/113) of LRTI patients with and without viral etiology, respectively, and this difference was also significant (p< 0.05). In conclusion, the long term follow-up is important in young children with viral LRTIs for the early diagnosis of complications. Thus the identification of viruses might aid in estimation of prognosis.