Respiratory syncytial virus infections in Croatia, 1994-99
Objective: to determine epidemiological characteristics, i.e. the occurrence of respiratory syncytial virus (RSV) infection in Croatian children with acute respiratory tract infections. Methods: At Virology Department, Croatian National Institute of Public Health (CNIPH), we tested nasopharyngeal secretions obtained from 1232 patients most of whom were hospitalized in two Zagreb hospitals for acute respiratory infections. Demonstration of the virus was by isolating it in cell culture and/or by detecting it with monoclonal antibodies in the direct immunofluorescence assay. Resultats: Most often, the virus demonstrated was RSV (43.8% ; 540/1232). Other respiratory viruses (adeno, parainfluenza, influeza) were shown considerably less commonly (5.1%). Viral infection could not be demonstrated in 629 (51.1%) patients. As to bronchiolitis, RSV was demonstrated to be its most common cause (60.77% ; 251/412). It was also proven to be the most common causative agent of infections in children aged 0-6 months (55.6% ; 300/540). Bronchiolitis (63% ; 190/300) and, less commonly, pneumonia (9.7% ; 29/300) were the diagnoses linked with RSV in this age group. On the other hand, RSV was demonstrated in 21%(63/300) of the children diagnosed with upper respiratory tract infection (URTI). We showed the presence of the majority of RSV infections in winter months, i.e. between November and June. Conclusion:RSV is a common cause of lower respiratory tract infections in Croatian infants and young children with its annual outbreaks occurring in winter season. Their onset is mostly in November.