The decay of coronavirus in sewage pipes and the development of a predictive model for the estimation of SARS-CoV-2 infection cases based on wastewater surveillance

  1. Songzhe Fu
  2. Qingyao Wang
  3. Fenglan He
  4. Can Zhou
  5. Jin Zhang
  6. Wen Xia

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Abstract

Wastewater surveillance serves as a promising approach to elucidate the silent transmission of SARS-CoV-2 in a given community by detecting the virus in wastewater treatment facilities. This study monitored the viral RNA abundance at one WWTP and three communities during the COVID-19 outbreak in the Yanta district of Xi’an city from December 2021 to January 2022. To further understand the decay of the coronavirus in sewage pipes, avian infectious bronchitis virus (IBV) was seeded in two recirculating water systems and operated for 90 days. Based on the viral abundance in the wastewater of Xi’an and the above data regarding the decay of coronavirus in sewage pipes, Monte Carol simulations were performed to estimate the infectious cases in Xi’an. The results suggested that the delta variant was first detected on Dec-10, five days earlier than the reported date of clinical samples. SARS-CoV-2 was detected on December 18 in the monitored community two days earlier than the first case and was consecutively detected in the following two sampling times. In pipelines without biofilms, the results showed that high temperature significantly reduced the viral RNA abundance by 2.18 log 10 GC/L after experiencing 20 km travel distance, while only a 1.68 log 10 GC/L reduction was observed in the pipeline with a low water temperature. After 90 days of operation, the biofilm matured in the pipeline in both systems. Reductions of viral RNA abundance of 2.14 and 4.79 log 10 GC/L were observed in low- and high-temperature systems with mature biofilms, respectively. Based on the above results, we adjusted the input parameters for Monte Carol simulation and estimated 23.3, 50.1, 127.3 and 524.2 infected persons in December 14, 18, 22 and 26, respectively, which is largely consistent with the clinical reports. This work highlights the viability of wastewater surveillance for the early warning of COVID-19 at both the community and city levels, which represents a valuable complement to clinical approaches.

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  1. ScreenIT

    SciScore for 10.1101/2022.03.16.22272521: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Thus, the infection cases can be modeled by the following equation (5) (community model):The Monte Carol simulation was built in Excel (Microsoft, Redmond, WA) with ModelRisk version 6.0.
    Excel
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    There are two limitations of this study. First, SARS-CoV-2 was replaced by IBV to understand the dynamics of CoV in the wastewater pipeline. Ideally, it would be much better to use intact SARS-CoV-2 seeding in the pipeline; however, this is not possible due to high biological safety level requirements for working with SARS-CoV-2 in a pilot-scale wastewater treatment plant. Therefore, a comparative study using SARS-CoV-2 as seeding material is needed to assure the reproducibility of the modeling. However, the results from Ahmed et al. (2020) showed that the decay rates of MHA and SARS-CoV-2 were comparable across all treatments with no significant difference, indicating the feasibility of using other CoVs for such analysis[22]. Nevertheless, comprehensive comparative studies are needed to reach a consensus on the surrogate virus used in modeling. Another limitation is that there is also significant uncertainty and variations in the model input parameters, especially for the distribution of SARS-CoV-2 RNA concentrations in stool and urine and the volume of excreta produced to the sewer system. This paper is largely limited to currently available data, and future modeling with updated input parameters with more specific and representative data would further improve the accuracy. However, uncertainty and variations do not preclude the usefulness of the Monte Carol model to infer the person infected. Despite the high variability within and between individuals, both the community m...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

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  2. Version published to 10.1101/2022.03.16.22272521v2 on medRxiv
  3. Version published to 10.1101/2022.03.16.22272521v1 on medRxiv