Arizona universities use wastewater to track virus

Northern Arizona University wanted to test campus wastewater for traces of COVID-19, a process that can serve as an early-warning system for new outbreaks.

One way to do that is with a composite sampler, but the machines come with a price tag of $5,000 each, which put the project out of reach. So the university searched for a simpler, less expensive alternative, said Crystal Hepp, an assistant director of the Pathogen and Microbiome Institute at NAU and an assistant professor at the School of Informatics, Computing, and Cyber Systems.

The answer was a method invented half a century ago and relied on a basic hygiene product: tampons, in this case, o.b. brand tampons, turning what has always been a girl’s best friend into something just as valuable to researchers.

It’s part of a larger effort among Arizona’s universities to use wastewaterbased epidemiology to monitor the spread of the novel coronavirus and learn more about its spread. State officials have made additional money available for the work and universities like NAU are hoping for more help to expand their research.

In the meantime, researchers are stretching their dollars with ideas like NAU’s. Hepp said when the university looked at the high cost of composite samplers or even the possibility of portable samplers, it was clear the cost was too high. So they went back in time, to when something called the Moore Swab was first used.

In 1946, Brendan Moore, a researcher, was given the task of testing for paratyphoid fever cases in England. Moore took a long strand of cotton or gauzelike material, rolled it up and submerged it in a manhole. After a time, the cotton was taken back to the lab and analyzed.

From 1948 to 1986, this method was considered instrumental in finding pathogens for typhoid and paratyphoid fevers, among other things, and became known as the Moore Swab.

Hepp said instead of reinventing the wheel, researchers at NAU realized tampons would work just the same.

“It’s accessible,” Hepp said. “It’s not just whoever has $5,000 to spend on all these composite samplers, it’s accessible to whoever wants to implement this kind of surveillance system.”

Hepp said the operation is partially funded by a bridge grant, but the team would like the state to offer financial support.

“We wish that we could fund it better,” Hepp said.

On Sept. 24, Gov. Doug Ducey announced Arizona universities would be receiving $8 million “for additional testing, surveillance and other response efforts at all three universities, including expanding wastewater testing.”

An additional $6 million would go to Arizona State University for point-ofneed testing.

C.J. Karamargin, director of communications for the governor’s office, confirmed all three universities, ASU, NAU and the University of Arizona, have received their portion of the funding but he could not confirm when the money was received.

With the additional $6 million for point-of-need testing, ASU received a total of $8 million. UA received $4 million and NAU received $2 million.

UA was the only university whose funding went directly to wastewater testing, with $335,000 earmarked for wastewater-based epidemiology. Karamargin said the money would be received after the expenses were collected.

NAU’s communication team confirmed the $2 million the university received from the state adding, “before and after this award, NAU has provided resources to support our wastewater testing efforts.”

Along with wastewater treatment, NAU is implementing mitigation testing, in which 2,500 random NAU community members are selected for a saliva test, according to NAU’s COVID-19 page. Wastewater-based epidemiology is used with mitigation testing to locate where there might be a potential COVID-19 outbreak.

“There have been situations where the wastewater testing has informed asymptomatic cases that were pulled out of population and allowed to be cleared to quarantine,” Hepp said. “It’s really hard to say if you prevented an outbreak that never happened.”

In September, the town of Guadalupe, near Tempe and Chandler, was seeing a high concentration of COVID-19 cases.

The community, which is primarily Hispanic and Native American, was contacted by ASU, which pointed out the infection levels in Guadalupe’s sewage system. Researchers said the town likely was seeing community spread.

The information from ASU and Tempe came from a COVID-19 wastewaterbased epidemiology dashboard. Rolf Haden, director of the Center for Environmental Health Engineering at the Biodesign Institute at ASU, said this was the first dashboard for COVID-19 and wastewater.

Testing wastewater for a variety of different things is not a new concept to ASU, where researchers introduced a program to test Tempe’s wastewater for drugs and alcohol.

ASU has used composite samplers to test wastewater, instead of the other common method, referred to as “grab sampling.”

With grab sampling, a sample is taken at one moment, while composite sampling relies on numerous samples over a period of time — for example, a sample every hour for 24 hours.

Halden said while science has proven grab sampling works, it relies more on chance than composite sampling since the sample might not be grabbed at the correct moment.

“The issue is if you think about how often you go and do big business every day, if it’s once or twice maybe, it’s a rare event,” Halden said referring to bathroom habits. “So, in order to catch that signal you have look the entire day, ideally, in order to find it.”

Though composite sampling could prove to be more effective, the high cost of composite samplers may not be accessible to everybody.

The University of Arizona is also using wastewater testing to understand and prevent COVID-19 on campus.

Ian Pepper, director of UA’s Water and Energy Sustainable Technology Center, said while wastewater testing is not eliminating the spread of COVID-19 from the campus, it has helped to reduce it.

UA began classes on Aug. 24 and found COVID-19 in the wastewater on Aug. 25 in Likins Hall. With that information, the university made the decision to test the residents of the dorms and found two students who tested positive for COVID-19.

“(Wastewater-based epidemiology) is very useful for monitoring the progress of a pandemic and it’s particularly useful for anticipating the initiation of a pandemic. As you probably know it’s a leading indicator,” Pepper said. “When someone is infected, they start getting the virus up to seven days before symptoms developing.”

UA was able to prevent further spread using the grab-sampling method, while pairing it with clinical testing.

According to an analysis by NPR in October, 65 U.S. colleges are testing wastewater for COVID-19 and the number is constantly growing.

Pepper said the UA had thought about doing wastewater testing for a while and when the pandemic struck it seemed like the perfect opportunity to test the theory.

“In the past six months you’ve seen an explosion of wastewater-based epidemiology across the United States and internationally — Japan, Canada, Europe, Australia, South Korea — you name it, they are doing it,” Pepper said.