The Development of Improved Virus Concentration Methods to Assess and Mitigate the Risks Associated with Handling Wash Waters Following Site Decontamination.
Citation:
Hurst, B., A. Korajkic, AND B. McMinn. The Development of Improved Virus Concentration Methods to Assess and Mitigate the Risks Associated with Handling Wash Waters Following Site Decontamination. ASM Microbe 2023, Houston, TX, June 15 - 19, 2023.
Impact/Purpose:
This research provides an effective concentration method to assess virus contamination in used wash waters following a contamination event.
Description:
Background: Site decontamination following a biological contamination event can expose first responders to dangerous microbial agents present. To deploy appropriate site mitigation strategies, microbiological agents present must be identified to ensure proper precautions are taken. Due to their resistance to disinfection and low infectious dose, human pathogenic viruses are a threat; however, effective field deployable methods for their detection in wash waters used for decontamination have yet been developed. Materials: A simulated, used decontamination wash water, was created using dechlorinated tap water containing a mild surfactant (0.05% Tween 80). To determine virus recovery efficiencies using dead end hollow-fiber ultrafiltration (D-HFUF), measured amounts of somatic and F+ coliphage were spiked into 2-liter volumes of simulated used wash water under the following scenarios: 1) wash water was directly amended with measured amount of sterile river sediment with no sediment separation prior to filter concentration; or 2) sediment added to wash water allowed to settle prior to filter concentrating clarified liquid portions, while resulting sediment was subjected to viral extraction techniques to optimize recovery of attached virus particles; and 3) optimized method was deployed on both non-porous and porous surfaces to mimic a site decontamination clean-up event. Results: Separation of sediment particles prior to D-HFUF significantly increased recovery of both coliphages, (P=<0.0001) over filtration of sediment and liquids simultaneously. Viral sediment elution techniques were evaluated to recover virus attached to particulate matter in wash water. A tryptic soy broth (TSB) elution solution proved significantly more effective (P=0.010 to <0.0001) for recovery of both somatic and F+ coliphage, (108±9% and 92±9%, respectively), compared to elution buffers various containing surfactants (sodium hexametaphosphate, Tween 80). Applying the method (sediment separation and optimized sediment elution protocol) resulted in recoveries of 96±19% (permeable surface) and 71±44% (non-permeable surface) for somatic and 75±31% for permeable surface and 92±19% from non-permeable surfaces for F+. Conclusions: Sediment particles were found to significantly impact recovery of viruses during filter concentration; allowing particulate matter settling (and separate processing), greatly increased recoveries for both virus types. Solutions used to release particulate bound viruses can significantly impact viral recoveries, highlighting the importance of evaluating each step of an effective recovery protocol.
