The investigation of respiratory syncytial virus (RSV) infection incidence in children with lower respiratory tract infection

RSV infection is the major cause of lower respiratory tract infections with high mortality and morbidity in infants and children worldwide. The aim of this study is to investigate the incidence of RSV infections in hospitalized infants and children with lower respiratory tract infection. The rapid and accurate laboratory diagnosis of RSV infection is important for the initiation of antiviral therapy and taking timely prevention and control precautions. In addition, it will reduce inappropriate antibiotic use and the duration of hospitalization. Total 323 hospitalized patients (0-15 years old) with lower respiratory tract infection were included in the study during January 2011- January 2012. In nasopharyngeal swab specimens collected from the patients by using flocked swabs (Copan Diagnostics, Italy), RSV antigen was investigated by direct immunofluorescent test (DFA, Argene SA, France) and RSV RNA analysed by nested RT-PCR. RSV RNA was found to be positive in 95 (29,4 %) of total 323 samples by RT-PCR and RSV antigen in 88 (27,6 %) samples by DFA. Of the samples, 80 (25 %) were positive and 220 (68 %) were negative by both of tests. Comparing with RT-PCR, the sensitivity of DFA test was 84,2 %, its specificity was 96,5 %, its positive predictive value was 91 % and its negative predictive value was 93,6 %. The incidence of RSV infections in the study group was rather high with the rate of 29,4 %. In conclusion, to start antiviral therapy early and to reduce the nosocomial transmission, it is suggested to use DFA test as the first diagnostic test which is more rapid and has high sensitivity with 84 % and the samples found to be negative should be tested by RT-PCR.