Method provides a four- to ten-day early warning on impending outbreaks, experts say.
Published on: 04-07-2021
Faculty and students from Loma Linda University School of Public Health have been monitoring possible COVID-19 exposure by testing wastewater on the school campus in Loma Linda, California, United States.
Ryan Sinclair, professor in the School of Public Health, has applied Wastewater Based Epidemiology (WBE) as an innovative method of surveillance. Wastewater monitoring has been used historically to track enteric viruses and other pathogens, including the poliovirus vaccine and wildtype strains, norovirus, and others, and drugs such as opioids, but at generally smaller scales.
The WBE method has been shown to provide a four- to ten-day early warning on impending COVID-19 outbreaks. Through this method, Sinclair and his team of students can detect a single infected individual among hundreds of dorm students.
“The RNA from COVID-19 can be detected in feces early in the infection before clinical symptoms. This makes wastewater a perfect tool to monitor potential infections in buildings on campus,” Sinclair said. “We are tracking COVID-19 RNA signals in dorms and other buildings on campus. We have been monitoring the wastewater since September 2020 and now have a system where the wastewater can be part of our overall multi-layered COVID-19 response.”
The team uses a testing method called Reverse Transcriptase quantitative Polymerase Chain Reaction (RT qPCR). It is using this project to test wastewater for pathogens and investigate the most cost-effective methods for use in the laboratory using available sampling, concentration, and extraction technologies. They have taken weekly samples from two sites on campus since September 2020 and will continue throughout the pandemic.
The team has also partnered with the wastewater treatment plant from the nearby city of San Bernardino and processes a weekly sample from that facility. During the pandemic, the team was able to find that the occurrences of infections within confined populations on campus and in private elementary schools were higher than the concentrations that occurred in the larger San Bernardino wastewater treatment plant.
“We can test for COVID-19 in the wastewater on campus and other pathogens if we are interested,” Sinclair said. “Several other pathogens can be monitored in this way. I have used this to monitor to detect listeria, campylobacter, and salmonella in communities within Fresno County.”
The project also allows students to apply classroom learning to real-world problems. “This is also a great way for students to experience hands-on epidemiology while studying at LLU,” Sinclair added. “There are several research questions to explore.”
Jashmer Dhillon, a Master of Public Health epidemiology student at the School of Public Health, said he would never have thought using water surveillance could be a valid method to maintain surveillance over COVID-19.
“We have had success in finding COVID-19 by analyzing sewage water,” Dhillon said. “I have been on the project for about three months, and we are constantly improving our methods and trying to find the best way to do water surveillance. In this project, I have learned how to filter and extract RNA from sewage water and replicate it using the PCR.”