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Testing poop to predict Miami's COVID-19 trends? It's been a messy process so far

By Adriana Brasileiro, Miami Herald on

Published in News & Features

Some wastewater sampling programs also are being implemented by other states. Since July, the Wisconsin State Laboratory of Hygiene in partnership with the University of Wisconsin, Milwaukee and the state Department of Natural Resources has been testing samples from wastewater treatment plants once a week in about 20 counties with 75% of the population. Universities such as Yale and the Massachusetts Institute of Technology are also testing their sewage to track the COVID pandemic in their communities. The University of Miami is also starting its own program, sampling sewage from different collection points at its campuses.

It's not clear if Florida is working on a state-funded program because neither the Department of Health nor Gov. Ron DeSantis' office replied to requests for comment.

At the national level, the Centers for Disease Control and Prevention and the U.S. Department of Health and Human Services announced last month it is starting the National Wastewater Surveillance System to generate data to "help public health officials to better understand the extent of COVID-19 infections in communities."

CDC is currently developing a portal for state, tribal, local, and territorial health departments to submit wastewater testing data into a national database, to be used for public health action.

Data from wastewater testing are not meant to replace existing COVID-19 surveillance systems, but are meant to complement them by providing data for communities where timely COVID-19 clinical testing is underutilized or unavailable, the CDC said.

In the meantime, Biobot is using poop data from cities to do all kinds of epidemiological studies. For example, the lab discovered that people with COVID shed a larger viral load in their poop in the first few days of infection. So if sewage samples show a significant increase in viral load, it means that a spike in case numbers could happen in about a week or so, Ghaeli said.


Statistically speaking, when people are contaminated with the virus, they will likely show symptoms on day four or five. They will probably want to get tested, and if the system is not overwhelmed, test results would probably be available in two or three days. So the test result would trail the start of infection by about a week or more.

If the poop testing is done efficiently, it could provide public health officials with some advance warning about trends.

Lynskey said the county may decide to do more targeted sewage testing to identify hot spots and obtain a more granular view of infection trends.

"We could test individual grid points in our system. We can do more localized samples rather than sampling at the treatment plant," he said. "We could do them from more focused basins and start honing down on where the infections are more problematic."

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