ABSTRACT Human polyomaviruses are emerging pathogens that infect a large percentage of the human population and are excreted in urine. Consequently, urine that is collected for fertilizer production often has high concentrations of polyomavirus genes. We studied the fate of infectious double-stranded DNA (dsDNA) BK human polyomavirus (BKPyV) in hydrolyzed source-separated urine with infectivity assays and quantitative PCR (qPCR). Although BKPyV genomes persisted in the hydrolyzed urine for long periods of time ( T 90 [time required for 90% reduction in infectivity or gene copies] of >3 weeks), the viruses were rapidly inactivated ( T 90 of 1.1 to 11 h) in most of the tested urine samples. Interestingly, the infectivity of dsDNA bacteriophage surrogate T3 ( T 90 of 24 to 46 days) was much more persistent than that of BKPyV, highlighting a major shortcoming of using bacteriophages as human virus surrogates. Pasteurization and filtration experiments suggest that BKPyV virus inactivation was due to microorganism activity in the source-separated urine, and SDS-PAGE Western blots showed that BKPyV protein capsid disassembly is concurrent with inactivation. Our results imply that stored urine does not pose a substantial risk of BKPyV transmission, that qPCR and infectivity of the dsDNA surrogate do not accurately depict BKPyV fate, and that microbial inactivation is driven by structural elements of the BKPyV capsid. IMPORTANCE We demonstrate that a common urinary tract virus has a high susceptibility to the conditions in hydrolyzed urine and consequently would not be a substantial exposure route to humans using urine-derived fertilizers. The results have significant implications for understanding virus fate. First, by demonstrating that the dsDNA (double-stranded DNA) genome of the polyomavirus lasts for weeks despite infectivity lasting for hours to days, our work highlights the shortcomings of using qPCR to estimate risks from unculturable viruses. Second, commonly used dsDNA surrogate viruses survived for weeks under the same conditions that BK polyomavirus survived for only hours, highlighting issues with using virus surrogates to predict how human viruses will behave in the environment. Finally, our mechanistic inactivation analysis provides strong evidence that microbial activity drives rapid virus inactivation, likely through capsid disassembly. Overall, our work underlines how subtle structural differences between viruses can greatly impact their environmental fate.
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Predictive Modeling of Virus Inactivation by UV
UV254 disinfection strategies are commonly applied to inactivate pathogenic viruses in water, food, air, and on surfaces. There is a need for methods that rapidly predict the kinetics of virus inactivation by UV254, particularly for emerging and difficult-to-culture viruses. We conducted a systematic literature review of inactivation rate constants for a wide range of viruses. Using these data and virus characteristics, we developed and evaluated linear and nonlinear models for predicting inactivation rate constants. Multiple linear regressions performed best for predicting the inactivation kinetics of (+) ssRNA and dsDNA viruses, with cross-validated root mean squared relative prediction errors similar to those associated with experimental rate constants. We tested the models by predicting and measuring inactivation rate constants of a (+) ssRNA mouse coronavirus and a dsDNA marine bacteriophage; the predicted rate constants were within 7% and 71% of the experimental rate constants, respectively, indicating that the prediction was more accurate for the (+) ssRNA virus than the dsDNA virus. Finally, we applied our models to predict the UV254 rate constants of several viruses for which high-quality UV254 inactivation data are not available. Our models will be valuable for predicting inactivation kinetics of emerging or difficult-to-culture viruses.
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- Award ID(s):
- 2023057
- PAR ID:
- 10215611
- Date Published:
- Journal Name:
- Environmental Science & Technology
- ISSN:
- 0013-936X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.est.0c07814
