Environmental Engineers and Scientists have Important Roles to Play in Stemming Outbreaks and Pandemics Caused by Enveloped Viruses

As described in our previous post, the journal Environmental Science and Technology have released a virtual issue providing an “Overview of Research on the Fate and Behaviour of Enveloped Viruses in the Environment”. That virtual issue was guest-edited by Alexandria B. Boehm and Krista R. Wigginton, two leading researchers on the fate of viruses in urban water systems.

The first article available in the virtual issue is a scientific “viewpoint” (non-peer reviewed) article by Wigginton and Boehm. In it, they make the case that “environmental engineers and scientists have important roles to play in stemming outbreaks and pandemics caused by enveloped viruses”.

Wigginton and Boehm highlight the limited data available on the concentrations of enveloped viruses in faeces and urine. This is despite the fact that aerosolised faecal particles are believed to have played a major role in the 2003 SARS outbreak at a Hong Kong apartment complex.

Nonetheless, Wigginton and Boehm conceptually step through the main aspects of the ‘microbial risk assessment’ logic that underpin the design and operation of urban water systems to protect public health from viral pathogens. They point out that many of the current design factors have been based on meeting higher challenges than those likely to be presented by SARS-CoV-2. For example, while there are still many knowledge gaps to fill, current indications are that SARS-CoV-2 may have:

  • lower excretion rates than human enteric human viruses,
  • faster inactivation rates in wastewater and other waters than nonenveloped viruses,
  • greater susceptibility to chlorine and other chemical disinfectants than nonenveloped viruses, and
  • greater susceptibility to UV inactivation than enteric single-stranded RNA viruses.

The authors suggest that higher risk exposures of SARS-CoV-2 may occur in communities that:

  • experience combined sewage overflows,
  • do not have sewage infrastructure,
  • use wastewater for irrigation,
  • include buildings that have faulty plumbing systems, or
  • have occupational exposures to wastewater and excrement.

Having considered the published evidence and associated knowledge gaps, Wigginton and Boehm provide suggestions for the focus of future studies. These include the need for improved characterisation (or standardisation) of the conditions under which studies are undertaken and the need to include well-studied surrogate viruses in experiments, so that results can be effectively cross-compared.

They also call for more research into the development of predictive models based on the underlying mechanisms controlling the persistence of enveloped viruses, and the analysis of sewage to monitor virus circulation in communities and rapidly detect outbreaks.

Most importantly, Wigginton and Boehm argue that environmental science and engineering researchers should take a broader, longer-term, and more quantitative approach to understanding viruses that are spread through the environment. By doing this, they should seek to understand how environmental factors shape possible virus transmission routes.

That way, regardless of the identity of a virus that may be responsible for a future outbreak, environmental science and engineering researchers can provide more informed descriptions of its expected persistence and recommendations on how to effectively mitigate environmental transmission.

REFERENCE:

Wigginton KR and Boehm AB (2020) Environmental Engineers and Scientists Have Important Roles to Play in Stemming Outbreaks and Pandemics Caused by Enveloped Viruses. Environmental Science & Technology.

https://doi.org/10.1021/acs.est.0c01476

Published by Stuart Khan

Professor of Civil & Environmental Engineering, University of New South Wales

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