Comparisons of a novel industrial hygiene filter material, wash solutions, and extraction methods in the detection and quantification of influenza virus

The World Health Organization (WHO) estimates that influenza epidemics cause 5 million cases of severe illness and 500,000 deaths worldwide. Few researchers have been able to detect influenza virus using samplers and methods currently available. Therefore, new samplers and methods should be considered.

This study compared influenza virus recovery from three filter types (PTFE, PVC, and PS) treated with or without sampling air, using HBSS or PBS wash buffer for virus removal, and the QIAamp Viral RNA Mini Kit or Trizol method for RNA extraction. Twenty, 30-minute laboratory trials were completed controlling relative humidity at 50%. Samples were analyzed using RT-qPCR.

Viral recovery for each filter type was significantly different (p-value < 0.0001), with viral recovery from PS being the highest. Treating filters with sampling air did not affect the recovery of viral RNA from the filter materials (p-values = 0.615, 0.947, 0.224, and 0.1122). Using HBSS and PBS resulted in viral recoveries that were significantly different, depending on the extraction method used (p-values = 0.0001, 0.0001, 0.0322, and 0.499). Viral RNA counts were significantly different between the Kit and Trizol extraction methods for all comparisons (p-values = 0.0021, 0.0013, 0.0001, and 0.0002).

Our results demonstrated that the novel PS filter material resulted in the highest counts of viral RNA, and that sampling air did not have a significant effect on viral recovery. Also, that the combination of HBSS with QIAamp Viral RNA Mini Kit, and PBS with the Trizol method, resulted in the highest counts of RNA extracted.