Etiology of acute respiratory infections in infants: A prospective birth cohort study

Abstract

Background: Acute respiratory infections (ARI) is continue to be the leading cause of mortality and morbidity in under five children from infectious diseases worldwide. There are paucity of studies on etiology of ARI in infants from developing countries. Our aims of this study are to document incidence and etiology of ARI in infants, their seasonal variability and association of clinical profile with the etiology. Methods & Materials: A cohort of newborns (310) were followed for the first year of life; for each episode of ARI, nasopharyngeal aspirates were collected and tested for virus with multiplex real time PCR assay. For lower respiratory infections (LRTI) additionally blood culture, serum procalcitonin, serum antibodies to Mycoplasma and Chlamydia and urinary Streptococcal pneumoniae antigen were also assayed. Results: A total of 503 ARI episodes were documented at incidence rate of 1.8 episodes per infant per year. Of these samples were processed in 395 episodes (URTI: 377 & LRTI: 18). One or more viruses were detected in 250 (63.3%) episodes and viral coinfections in 72 (18.2%). Rhino virus (RV) was the commonest virus [105 (42%)] followed by Respiratory syncytial virus (RSV) [50 (20%)], Parainfluenza [42 (16.8%)] and Corona virus [44 (17.6%)]. In LRTIs viruses were detected in 12 (66.7%), bacterial infections in 17 (94.4%) and mixed bacterial–viral infection in 8 (44.4%) episodes. Maximum incidences of most viruses were during month of February- March and September- November. There was no significant difference in symptom duration with virus types.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Conclusion: In this cohort of infants, ARI incidence was 1.8 episodes per year per infant; 95% were URTIs. Viruses were identified in 63.3% episodes and the common viruses detected were RV, RSV and parainfluenza virus.