Quantitative PCR for cannabis flower containing SARs-CoV-2

  1. Kevin J. McKernan
  2. Liam T. Kane
  3. Yvonne Helbert

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Abstract

In January of 2020, COVID-19 became a worldwide pandemic. As many industries shutdown to comply with social distancing measures, the cannabis industry was deemed an essential business in most U.S. jurisdictions. Cannabis is manually farmed, trimmed and packaged. Employees and trimmers in cannabis grows have been reported to test qPCR positive for SARs-CoV-2 and as a result cannabis flower can be a potential inhaled SARs-CoV-2 fomite. Many of the comorbidities described in COVID-19 are also qualifying conditions for medical cannabis access. Bat guano has been identified as a rich source for novel coronavirus discovery and it is also a common fertilizer in the cannabis field. To better assess cannabis fomite risk we developed a SARs-CoV-2 quantitative PCR assay optimized to operate with a hemp flower background matrix. This assay was utilized to estimate the stability of gamma irradiated SARs-CoV-2 as a hemp flower fomite.

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  1. ScreenIT

    SciScore for 10.1101/2020.06.06.112474: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Experimental Models: Cell Lines
    SentencesResources
    This places constraints on measuring viral “viability” that is traditionally assayed by counting plaques on Vero cell lawns.
    Vero
    suggested: CLS Cat# 605372/p622_VERO, RRID:CVCL_0059)

    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:
    One limitation to this study is the use of cured cannabis samples. The polymerase utilized in this study has reverse transcriptase (RT) activity and will amplify both DNA and RNA. Non cured samples are likely to have higher RNA levels which may favor amplification of the cannabis internal control over the viral target. Experiments with DNAse treatment of these hemp samples demonstrated major shifts (5-8 Cq shift) in Cq suggesting very little contribution from Cannabis RNA but this may need further investigation for testing un-cured cannabis or different cannabis tissues. To date, SARs-CoV-2 has never been detected on cannabis and cannabis is not believed to be a corona virus replicative host. It is possible for manually curated cannabis flower to become a fomite. It is doubtful virions will survive extraction or pyrolysis of cannabis flower but vaporization of cannabis flower and cannabis pre-rolls are documented microbial vectors (Remington et al. 2015; Shapiro Bb Md et al. 2018). Sterilization of SARs-CoV-2 requires 65 °C treatment for 30 minutes (ATCC part # 1986HK). Cannabis vaporization is usually performed over 130 °C but with a few seconds of duration. It is not yet known if this process will properly sterilize cannabis of SARs-CoV-2, but it has failed to sterilize cannabis of Aspergillus spores and resulted in clinical cases of Cannabis derived aspergillosis. While chances of cannabis supply chain contamination with SARs-CoV-2 are remote, the RNA of the virus is stabl...

    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.
    • No funding statement was detected.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2020.06.06.112474v1 on bioRxiv