Rapid detection of respiratory viruses by centrifugation enhanced culturesfrom children with acute lower respiratory tract infections

Background: Acute respiratory tract infection (ARI) is the major cause of m orbidity and mortality in young children in developing countries. Informati on on viral aetiology in ARI in India is very limited. Objective: The aim o f the study was to define the role of viruses in acute lower respiratory tr act infections (ALRTI) in children in India using centrifugation enhanced c ultures followed by indirect immunofluorescence (IIF). Study Design: Nasoph aryngeal aspirates (NPAs) were collected from children from September 1995 to April 1997, attending paediatric clinic of All India Institute of Medica l Sciences (AIIMS) with symptoms of ALRTI. Virus isolation was done by cent rifugation enhanced cultures using HEp-2, LLC-MK2 and MDCK cells. The virus es were identified at 24-48 h post inoculation by IIF staining using monocl onal antibodies to respiratory syncytial virus (RSV), parainfluenza virus ( PIV), influenza virus and adenovirus. Results: Of 200 NPA samples, 89 (44.5 %) were positive for one or more viral pathogens. RSV was detected in 34 (1 7%) of all ALRTI cases followed by influenza viruses in 29 (14.5%), PIVs in 23 (11.5%) and adenoviruses in three (1.5%). In 79 children with bronchiol itis, RSV was most frequently isolated (25%) pathogen, while in bronchopneu monia cases (101) the most common viral pathogen was influenza virus (17%). In eight cases (4%) of ALRTI dual infections were detected. In 100 NPA spe cimens IIF staining on direct cell smears was carried out and viruses were detected in only 17%. RSV and influenza virus infection peaked from Septemb er to December, where as PIV infections were more frequent from January to April. Conclusion: Respiratory viruses accounted for 44.5% of cases of ALRT I in India and the results of viral aetiology could be given in 24-48 h usi ng centrifugation enhanced cultures. RSV was the most common viral agent as sociated with ALRTI in children under 5 years of age with greater associati on with bronchiolitis (C) 2000 Elsevier Science B.V. All rights reserved.