New Castle County wastewater samples show more COVID-19 cases than reported

NEW CASTLE — Approximately 15,200 cases of COVID-19 may have been present in Delaware’s largest county as of April 15, according to recent analysis of wastewater bacteria, officials announced on Thursday.

According to a New Castle County news release, the first results indicated that 3% of the county’s population north of the C&D Canal had the coronavirus on April 15, approximately 15 times the published rate of confirmed, positive tests on that date.

County Executive Matt Meyer announced the preliminary test results drawn from tests of county and city of Wilmington sewers. Massachusetts Institute of Technology startup Biobot Analytics conducted the testing.

“We must do whatever we can to keep communities safe, and we must do it today,” Mr. Meyer said in a statement.

“This is a data point that may help better understand the prevalence of COVID-19 in our community. Anything that helps make this invisible enemy a little more visible is welcome.

“As we monitor readings in future weeks, we hope to gain insight that will help us flatten the curve, save lives, and begin preparations to safely return to work.

“We thank Biobot for this innovative partnership.”

As of 6 p.m. Thursday, according to the Delaware Division of Public Health, there were 1,486 laboratory confirmed cases in New Castle County, 558 in Kent County and 1,394 in Sussex County.

On Friday, DPH spokeswoman Stacey Hoffman was not aware of the study and thus could not comment.

Biobot Analytics President and co-founder Newsha Ghaeli said, “The biggest takeaways are that there are clearly a largely undiagnosed population similar to what we’re seeing around the country.

“Access to testing is limited and there are a large number of asymptomatic persons or ones with mild symptoms who may not be tested.

“It’s very important for us to know what (level of) population exists that still could be infected or contagious.”

New Castle County will pay $480 total in shipping costs during the four-week study, spokesman Brian Cunningham said Friday. About five fluid ounces are needed for a bottled sample that’s sent to Biobot Analytics, he said.

Ms. Ghaeli said the company is processing more than 150 samples weekly, and is working to expand testing capacity. New Castle County responded in the first week of April after Biobot Analytics launched an open call on its website on March 23.

So far, New Castle is the only Delaware county working with the lab.

On Friday afternoon, Kent County Administrator Michael Petit de Mange said he had only recently learned of the report and hadn’t yet conferred with Levy Court commissioners. He said the county would follow the state’s lead regarding wastewater contagion issues.

Sussex County spokesman Chip Guy said, “This is not something we have or are currently looking at, and it’s my understanding Biobot is tapped out on samples for the moment. They were supposedly soliciting samples from across the country.”

Mr. Guy stressed that the results “came from one facility, in the city of Wilmington. To do comprehensive sampling in Sussex would require testing from multiple facilities (county and municipal plants).

“That’s not something we or the municipalities have been requested or solicited to do at this point.”

Reach staff writer Craig Anderson at 741-8296 or

Helpful Coronavirus links

Delaware Division of Health Coronavirus Page
CDC: About the Coronavirus Disease 2019
CDC: What to do if You Are Sick
Johns Hopkins Coronavirus Resource Center
AP News Coronavirus Coverage
Reopening Delaware: Resources for Businesses
Delaware Phase 2 guidance

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