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Study of virus isolation from pharyngeal swabs in children with varicella
Insights
Virus isolation from children with varicella revealed low rates for varicella-zoster virus (VZV) but higher rates for cytomegalovirus (CMV) and herpes simplex virus (HSV). Filtration methods may impact VZV detection.
Area of Science:
- Virology
- Pediatric Infectious Diseases
- Molecular Biology
Background:
- Varicella (chickenpox) is a common childhood illness, typically caused by the varicella-zoster virus (VZV).
- Understanding viral shedding patterns in pharyngeal swabs is crucial for diagnosing and managing viral infections in children.
- Co-infections or other viral agents may be present in children diagnosed with varicella.
Purpose of the Study:
- To investigate the prevalence of various viruses, including VZV, in the pharyngeal swabs of children diagnosed with varicella.
- To compare viral isolation rates between children with varicella and healthy controls.
- To assess the impact of sample filtration on viral detection.
Main Methods:
- Virus isolation from pharyngeal swabs of 117 children with varicella and 70 healthy children using human embryonic lung cell cultures.
- Confirmation of viral isolates via indirect immunofluorescence or neutralization assays.
- Testing of filtered (0.45 microns) and unfiltered swabs for viral presence.
Main Results:
- VZV was isolated from 4.3% of varicella patients; CMV (19.7%) and HSV (4.3%) were more frequently detected.
- In healthy controls, CMV (14.3%) and HSV (2.9%) were also isolated.
- No VZV isolates were found in filtered swabs, while CMV and HSV were detected in both filtered and unfiltered samples.
Conclusions:
- The isolation rate of VZV from pharyngeal swabs in children with varicella is low compared to CMV and HSV.
- Filtration of samples may hinder VZV detection, suggesting VZV may not be readily culturable from pharyngeal swabs using this method.
- Further investigation into diagnostic methods and viral shedding characteristics is warranted.
Abstract:
We performed virus isolations from the pharyngeal swabs in 117 children with varicella who were aged from 22 days to 15 years and 70 healthy children who were aged from 3 months to 15 years, by using human embryonic lung cell cultures. Viral isolates were confirmed by an indirect immunofluorescence method or by neutralization with well-characterized antibodies. Five varicella-zoster virus isolates (4.3%), 23 cytomegalovirus isolates (19.7%), five herpes simplex virus isolates (4.3%), and one respiratory syncytial virus isolate (0.9%) were found in the patients with varicella. Ten cytomegalovirus isolates (14.3%), two herpes simplex virus isolates (2.9%), one respiratory syncytial virus isolate (1.4%), and one poliovirus isolate (1.4%) were found in the swabs of the healthy control children. The varicella-zoster virus isolation rate from the pharyngeal swabs in children with varicella was low as compared with the rate from those pharyngeal swabs in the children with cytomegalovirus and herpes simplex virus. No varicella-zoster virus isolates could be found in the swabbed materials after filtration (0.45 microns). On the other hand, cytomegalovirus and herpes simplex virus could be isolated from the filtrated swabs, as well as from the unfiltrated swabs. The method of testing by filtration could have affected the results.