Researchers at the University of Arizona Water and Energy Sustainable Technology Center are testing wastewater across the country to trace the prevalence of coronavirus in communities and to help public health officials prepare for the future.
WEST Center researchers already test for viruses in sewage and reclaimed water intended for reuse, such as to irrigate grass in parks and golf courses. Now, sewage surveillance can determine whether the novel coronavirus is present in a community, even if individuals are asymptomatic, as well as help ensure the effectiveness of a municipality’s wastewater treatment process.
“Testing the wastewater gives you an idea of the number of cases within a community and if the numbers are increasing or decreasing,” says Ian Pepper, director of the WEST Center and a member of the university’s BIO5 Institute. “The approach can also be used to help determine if an intervention is working to reduce the transmission of the virus.”
“We will be able to determine if the virus persists in the community even if there are no reported new cases,” says Charles Gerba, a microbiologist and professor of environmental science in the College of Agriculture and Life Sciences. “To me, it’s a key to tracing the spread of a virus.”
Environmental microbiologists have used sewage monitoring programs to study pathogenic viruses for decades, most notably in public health efforts to globally eradicate the poliovirus.
Through the development of the polio vaccine and global vaccination programs, the transmission of the poliovirus has fallen dramatically in the last 26 years. However, three countries have ongoing polio transmission — Nigeria, Afghanistan and Pakistan. Environmental surveillance programs have been used to pinpoint transmission of the poliovirus through viral shedding found in community wastewater.
With advanced laboratory capabilities and expertise in coronavirus research, the WEST Center is uniquely situated to conduct sewage surveillance for COVID-19. Located within the Pima County Wastewater Treatment Plant, the facility has extensive expertise in the detection of viruses in wastewater.
“We have tested for hepatitis A, enteroviruses and noroviruses. We have approximately 15 different viruses that we regularly test for in sewage and recycled waters for reuse applications,” says Walter Betancourt, a microbiologist with expertise in environmental virology and assistant research professor in the Department of Environmental Science.
Named for the crown-like spikes on their surface, coronaviruses were first identified in the mid-1960s. Worldwide, seven coronaviruses are known to infect people and cause illness, including SARS-CoV-2 — the novel coronavirus that causes COVID-19.
A 2008 study conducted by WEST Center researchers measured the survival of other coronavirus types in wastewater. They found that coronaviruses die off very rapidly in wastewater, with a 99.9% reduction in two to three days.
Now, researchers at the WEST Center will use molecular methods and nucleic acid targets recommended by the U.S. Centers for Disease Control and Prevention to detect genetic markers of the novel coronavirus in sewage samples collected prior to and following wastewater treatment.
As the new strain of coronavirus is investigated, the WEST Center hopes to correlate viral concentrations in sewage with recorded numbers of infections to help public health officials better prepare for the future.
Further investigations based on sewage surveillance and more recent next-generation sequencing approaches may also help identify variants circulating in the population and assess the effectiveness of mitigation strategies to control and prevent COVID-19.