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

E engineers and scientists have played pivotal roles in protecting the public from viral illnesses, and continue to do so today. We develop drinking water and municipal wastewater treatment technologies, make discoveries that inform related regulations and policies, and conduct critical research on the presence, persistence, and transport of viruses in the environment. A wide range of impactful research in our field has focused mainly on nonenveloped human enteric viruses such as human noroviruses and enteroviruses. More recently, a number of high-profile outbreaks such as Ebola virus, measles, Zika virus, avian influenzas, SARS, MERS, and the ongoing COVID-19 pandemic have been caused by enveloped viruses. In addition to the RNA or DNA genomes and protective protein capsids that are common to all viruses, enveloped virus structures are also wrapped in bilipid membranes. The primary mode of transmission for many enveloped viruses is by close contact with infected individuals. Some enveloped viruses, however, are released to the environment by the host and persist on surfaces (i.e., fomites), in the air, or in water, long enough to come into contact with another host for further onward transmission (i.e., indirect transmission). This includes viruses responsible for influenza and measles. The primary transmission routes for SARS-CoV-2 (the virus that causes COVID-19) are believed to be person-to-person contact and by exposure to large droplets produced from sneezing, coughing or talking, but indirect transmission routes may also play a role. This potential role of the environment in the spread of COVID-19 highlights the multitude of applied research needs that must be addressed to effectively control outbreaks and pandemics as novel enveloped viruses emerge. Environmental engineers and scientists are well positioned to apply their unique skill sets and experience with interdisciplinary research to address these needs. Virus particles in the air and on fomites are exposed to a range of environmental conditions that influence their persistence. Relative humidity, fomite material, and air temperature can greatly impact enveloped virus inactivation rates. Even the medium in which the virus is suspended can greatly impact persistence. For example, chlorine-based solutions and hydrogen peroxide gas are effective at inactivating the enveloped virus surrogate Phi6 on fomites, but the presence of blood requires much higher hydrogen peroxide gas doses. Future mechanistic studies should probe how specific constituents in the matrix, temperature, humidity, and solar radiation each impact inactivation. Furthermore, research quantifying the transfer of enveloped viruses between fomites and skin, and determining effective hand washing and surface sanitizing methods, is needed to inform agent-based risk assessment models. Viruses have a direct connection to wastewater and drinking water purification when they are excreted in feces or urine (Table 1), but there is limited data on the concentration of enveloped viruses in feces and urine. The human coronavirus responsible for the 2003 SARS outbreak was able to replicate in the human GI tract and infective particles were detected in stool samples. In fact, aerosolized fecal particles are believed