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Practical recommendations for the detection of pediatric respiratory syncytial virus infections
Insights
For optimal respiratory syncytial virus (RSV) detection in infants, nasal washes combined with immunofluorescence offer the quickest and most frequent isolation. Prompt specimen transport and timely inoculation are crucial for accurate RSV diagnosis.
Area of Science:
- Pediatric Infectious Diseases
- Virology
- Diagnostic Microbiology
Background:
- Respiratory syncytial virus (RSV) is a major cause of infant respiratory infections.
- Accurate and timely diagnosis of RSV is critical for patient management and infection control.
Purpose of the Study:
- To compare the diagnostic yield of different specimen types for RSV detection.
- To evaluate the efficacy of immunofluorescence for rapid RSV diagnosis.
- To determine optimal conditions for RSV isolation and specimen transport.
Main Methods:
- RSV isolation and immunofluorescence assays were performed on nasal washes, throat swabs, and nasopharyngeal swabs from infants.
- Specimen transport times and HEp-2 cell culture conditions were investigated.
- RSV antigen detection in intubation secretions was assessed using immunofluorescence.
Main Results:
- Nasal washes yielded RSV more frequently (84%) and sooner (4.2 days) than throat (45%; 5.5 days) or nasopharyngeal swabs (39%; 5.7 days).
- Immunofluorescence of nasal wash cells identified 72% of infants within one day.
- RSV infectivity was maintained for 6 hours at room temperature in phosphate-buffered saline.
Conclusions:
- Combining RSV isolation and immunofluorescence on nasal wash specimens provides optimal detection in infants.
- Prompt specimen transport (under 6 hours) and timely inoculation of HEp-2 cells (under 4 days old) enhance RSV recovery.
- Immunofluorescence is valuable for monitoring RSV antigen during antiviral therapy.
Abstract:
In our private clinic-hospital setting, respiratory syncytial virus (RSV) was isolated from infants more frequently and sooner from nasal washes (84%; 4.2 days) than from throat swabs (45%; 5.5 days) or nasopharyngeal swabs (39%; 5.7 days). Immunofluorescence of nasal wash cells identified 72% of the infants with virus isolations from nasal washes in less than one day. We therefore recommend the combination of isolation and immunofluorescence on nasal wash specimens for optimal detection of RSV-infected infants. Immunofluorescence of respiratory tract cells was also useful for monitoring the presence of RSV antigen in intubation secretions during ribavirin antiviral therapy. RSV infectivity was maintained in phosphate-buffered saline at room temperature for 6 h. Transport and inoculation of specimens in less than 6 h yielded RSV isolates from 50% of sampled infants during the two RSV seasons examined. For optimal RSV isolation, we recommend inoculation of HEp-2 tubes less than or equal to 4 days old. Replacing medium after 3 days as compared with 7 days did not increase recovery of RSV and provided little practical reduction in time to detection of cytopathology.