In January 2021, NIU started testing local wastewater for the presence of SARS-CoV-2, the virus that causes COVID-19. The program is the result of a partnership between NIU and the Kishwaukee Water Reclamation District. The water district provides samples of wastewater to be tested for SARS-CoV-2 by NIU scientists in a newly designed laboratory.
People infected with SARS-CoV-2 can shed the virus from their gastrointestinal tract into wastewater several days before symptoms might appear. Wastewater testing isn't new. Scientists have used it to detect other viruses and microbes in the past. In 2020, the field (called wastewater-based epidemiology or WBE) shifted to focus on the SARS-CoV-2 virus.
Benefits of Testing Wastewater
The SARS-CoV-2 virus is present in infected people's respiratory tracts, which is why nasal swabs and saliva-based tests are used to detect it. County health departments rely on these tests to report the number of COVID-19 cases in an area. Since they may not get tested, infected people with no symptoms may not be included in the reported number of cases.
Wastewater testing detects the virus in the feces of infected people, whether or not they have symptoms. So, it can provide a better estimate of the virus's spread in an area. One of the main benefits of wastewater testing is the potential to measure sudden and sustained increases in SARS-CoV-2 levels before healthcare facilities experience a surge in patients with symptoms. If such viral surges are detected, health departments can notify healthcare facilities to help them better prepare for the potential onslaught of COVID-19 patients.
How Wastewater Testing Works
Wastewater is a mixture of what goes down our drains and toilets. To test wastewater for the SARS-CoV-2 virus, scientists first concentrate the biological material in the water. Then, they extract genetic material called ribonucleic acid (RNA) from the concentrated mixture. Next, they test the RNA to determine how much of it is from the virus. Finally, they calculate the concentration of the SARS-CoV-2 virus per liter of wastewater. The results inform them how prevalent the virus is in an area.