The same wastewater surveillance techniques that have emerged as an important tool in the early detection of Covid-19 outbreaks are being adapted for use in monitoring the alarming spread of monkeypox throughout the San Francisco Bay Area and some other US communities.
Before the Covid pandemic, wastewater sludge was thought to hold promise as an early indicator of community health threats, as people could excrete genetic evidence of infectious diseases in their feces, often before they showed symptoms of illness. Israel has monitored wastewater for polio for decades. But before Covid, such risk monitoring in the US was largely limited to academic pursuits.
With the onset of Covid, a research collaboration involving scientists from Stanford University, the University of Michigan and Emory University has pioneered efforts to revamp surveillance techniques for detecting the Covid-19 virus, using wastewater for the first time. Track a respiratory disease.
That same research team, the Sewage Coronavirus Alert Network, or SCAN, is now a leader in expanding wastewater monitoring to detect monkeypox, a once-obscure virus in remote parts of Africa that has infected more than 26,000 people worldwide within months. And more than 7,000 across the U.S. The Biden administration declared the monkeypox outbreak a public health emergency last week, following similar decisions by health officials in California, Illinois and New York.
And SCAN’s scientists envision a future in which wastewater sludge serves as a reservoir for tracking alarming public health concerns. “We’re looking at a whole range of things that we might be able to test,” said Marlene Wolff, an assistant professor of environmental health at Emory.
Since increasing surveillance in mid-June, the SCAN team has detected monkeypox in several of the 11 Northern California sewers it monitors, including Palo Alto, San Jose, Gilroy, Sacramento and two locations in San Francisco. Funded by grants from the National Science Foundation and the CDC Foundation, SCAN is conducting similar monitoring in Colorado, Georgia, Michigan and four other states and intends to scale up to 300 US sites.
It is one of a growing number of sewage surveillance projects across the US run jointly by universities, public health agencies and utility departments that provide Covid results to state and federal agencies. It is unclear how many of these networks have extended their search to Monkeypox. Scan sites in California, Georgia, Michigan and Texas and a research team in Nevada are among the few to report sludge samples that tested positive for the monkeypox virus.
As with Covid, monkeypox data can be used to compare trends across regions, but there are limits to what this type of monitoring can do. Wastewater monitoring does not identify who is infected; It reveals the presence of only one virus in a particular area. And it takes an expert to analyze the sample. Researchers consider wastewater surveillance to complement, not replace, other public health tools.
“We’re still really at the forefront of discovering potential here,” said Heather Bischel, assistant professor of civil and environmental engineering at the University of California-Davis, which included wastewater monitoring as part of the Healthy Davis Together. Covid testing program for campus and surrounding community. “But what we’ve already seen shows that this kind of monitoring can be adapted to other public health threats.”
Some US communities were sampling sewage before the pandemic to determine what types of opioids residents were using. More recently, with Covid and monkeypox, the technology has shown promise for monitoring flu and respiratory syncytial virus, or RSV. The federal Centers for Disease Control and Prevention is planning pilot studies to see if sewage can reveal trends in antibiotic-resistant infections, foodborne illnesses and Candida aureus, a fungal infection.
Much of the wastewater testing done in the first year of the pandemic was done in conjunction with universities or county offices and relied on funding provided through the federal Covid Relief Act. At Bischel’s campus, those funds were combined with money from university donors for an extensive testing and treatment program that included wastewater monitoring for the school and the city of Davis. Sewage testing is underway in separate grants.
Currently, the CDC is only reporting Covid results in its national wastewater surveillance system, a reflection of the limited number of sewage sheds it has so far tested for monkeypox.
The global spread of monkeypox was first detected in the UK in May and it was speculated that the virus could also be passed into wastewater, either through faeces or when an infected person with an open sore takes a shower. Sewers in areas of infected people may then “light up” with evidence of the disease – if wastewater testing can identify it.
“It’s been enlightening,” said Brad Pollock, chair of public health sciences at UC Davis Health. “It works as a warning system, and you don’t have to persuade people to take individual tests to use the information; It’s passively collected, so you get a broader community look.”
The virus is believed to be primarily spread through close skin-to-skin contact and exposure to symptomatic lesions, although researchers are exploring other possible routes of transmission. For now, the U.S. outbreak is largely concentrated in gay communities among men who have sex with men.
The discovery of monkeypox in San Francisco’s wastewater system in June, the first of its kind in the country, raised alarm in a city with a thriving LGBTQ+ population. On July 28, San Francisco declared monkeypox a public health emergency, urging the federal government to increase distribution of its vaccine.
For Northern California surveillance, SCAN partners with local health officials and universities to collect samples and then send them to Verily Life Sciences — a health technology company owned by Alphabet, Google’s parent company — for analysis. In the Atlanta area, SCAN is working with health officials in Emory and Fulton counties.
Not all public health agencies are moving as quickly. A wastewater monitoring plan for the virus is now being put together in Los Angeles County alone, which confirmed more than 300 cases of monkeypox by the end of July.
And although California is collecting monkeypox data from its surveillance partners, it’s not available for all regions, with wastewater monitoring for the virus still an emerging method.
“With every new thing we add to the testing platform, we’re learning things,” says SCAN’s Wolfe. “The pandemic really sparked our imagination for a tool that already existed but wasn’t fully developed. That is changing now.”
This story was produced by KHN, which publishes California Healthline, the editorially independent service of the California Health Care Foundation.
KHN (Kaiser Health News) is a national newsroom that produces in-depth journalism about health issues. Along with policy analysis and polling, KHN is one of the three main operating programs of the KFF (Kaiser Family Foundation). KFF is a non-profit organization that provides health information to the nation.
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