RAPID DETECTION OF RESPIRATORY SYNCYTIAL VIRUS (RSV) IN NASOPHARYNGEAL WASH SPECIMENS

Question: Respiratory syncytial virus (RSV) has been accepted to be th e major cause of respiratory tract diseases in infants and young child ren. Especially premature infants, children with congenital heart or l ung diseases and immunocompromised patients are at high risk for life- threatening infection. Rapid diagnosis of RSV infections is needed bec ause of the availability of antiviral therapy, and for the prevention of nosocomial infections. Method: We processed a total of 343 specimen s, mostly (98%) nasopharyngeal washings collected from 330 pediatric p atients with clinical signs of respiratory infection, with an enzyme i mmunoassay for detection of RSV antigen and virus culture. Results: Re sults from both assays could be compared for 297 specimens, and were i dentical in 275 out of 297 (93%) specimens. Of 108 samples found to be positive by the enzyme immunoassay, 92 were culture positive for RSV. Out of 189 specimens negative by immunoassay, six were positive by cu lture. Due to the high lability of viral infectivity, the failure to d etect RSV by culture in 16 samples does not necessarily mean that ther e are false-positive reactions by the enzyme immunoassay. In 46 sample s, culturing of RSV was hampered by nasopharyngeal specimens contamina ted with bacteria or fungi, or by the presence of a fast growing non-R SV virus; 50% of them were positive by immunoassay. Conclusion: Since virus isolation is time-consuming and only successful when specimens a re transported to the laboratory without delay, and other assays for d etection of RSV need enormous methodical and technical efforts, an imm unoassay will be a simple and reliable method for the rapid detection of RSV.