Clinical and epidemiological manifestations of parainfluenza infection in hospitalized children

Background: Human parainfluenza viruses (hPIV) are a common cause of respiratory illness of children but published data on clinical characteristics of hPIV infection in South America is scarce. Objective: To review the clinical presentation and epidemiological features of hPIV in a series of hospitalized children in Chile. Patients and Methods: Retrospective review of clinical charts from all pediatric admissions with a diagnosis of respiratory disease (between January 2001 to December 2004) at the Catholic University Hospital, Santiago, Chile. Nasopharyngeal secretions were tested for hPIV in children admitted with suspected respiratory viral infections. Results: A total of 3,043 respiratory admissions were recorded during the study period; 64 children (2.1%) were hPIV positive. Average age was 13 months (range: 1 m to 12y) and 77% were younger than 2 years. HPIV-2 was the most common type identified (47%). A seasonal trend was noted for serotypes hPIV-2 and 3. Acute wheezing (40%) and pneumonia (30%) were the most common clinical diagnosis in hPIV positive children and 17% hPIV positive children (44% for hPIV-1) were associated with laryngitis. All hPIV positive bronchiolitis were due to serotypes hPIV-2 and 3. Conclusion: hPIV can cause respiratory disease requiring hospitalization; serotypes hPIV-2 and 3 displayed a seasonal trend. Although hPIV is an uncommon cause of severe respiratory infecion requiring hospitalization in children, it should be considered in the differential diagnosis of laryngitis, bronchiolitis and pneumonia, especially in younger children.