LAKE COUNTY, Calif. – Results from recent testing conducted at all of the sewer treatment plants operated by Lake County Special Districts have revealed the presence of the virus that causes COVID-19.

Special Districts reported the testing results on Friday.

Last month, Special Districts began participating in a project to look for evidence of SARS-CoV-2 – the name given by the World Health Organization to the novel coronavirus which causes COVID-19 – at the treatment plants it operates, as Lake County News has reported.

The firm Biobot, based in Somerville, Massachusetts, is conducting the surveillance testing for Special Districts as part of its COVID-19 response program.

A wastewater epidemiology firm with a mission of transforming wastewater infrastructure into public health observatories, Biobot launched its pro bono program to map COVID-19 across the U.S. in collaboration with researchers at MIT, Harvard and Brigham and Women's Hospital.

Special Districts said the goal is to track the virus’ intensity and spread across the country and provide public health agencies with data in responding to the pandemic.

Beginning on March 26, the tests began on a weekly basis at Special Districts’ sewage treatment plants. Results were available three to five days after each round of testing.

The agency said the first four samples taken on March 26 did not detect the virus; neither did the next round of samples taken on April 1.

However, samples taken on April 8 detected the presence of SARS-CoV-2 at all four treatment plants, Special Districts reported.

Three days earlier, on April 5, Lake County’s first COVID-19 case was confirmed and, since then, testing has confirmed five other cases.

“The presence of COVID-19 in all four treatment plants does suggest we may have community transmission,” Special Districts reported.

Lake County Public Health Officer Gary Pace said in a Friday statement that the test results of the untreated sewage confirmed suspicions from recent contact investigations that there have been some undetected infections in the county over the last month.

He also noted, “Recent evidence, including the raw sewage testing, does suggest it is probable community transmission of the coronavirus has occurred in Lake County,” explaining that it hadn’t been previously identified due to a lack of adequate testing.

So far, just over 300 tests have been conducted, and Pace said his agency is working hard to get more supplies and laboratory access, and the state is promising some changes in the coming weeks.

“Since there have been limitations in testing access, many people with mild illness in the community haven’t been able to be tested. However, it is reassuring we have not seen a rise in serious illness or hospitalizations,” Pace said.

The Centers for Disease Control and Prevention reported that while SARS-CoV-2 has been detected in the feces of some patients diagnosed with COVID-19, the amount of virus released from the body in stool, how long the virus is shed and whether the virus in stool is infectious are not known.

While it also isn’t known if there is risk for transmission from the feces of an infected person, the CDC said it’s expected to be low based on data from previous outbreaks of related coronaviruses, such as severe acute respiratory syndrome, or SARS, and Middle East respiratory syndrome, or MERS.

The CDC said that, based on data so far, the risk of SARS-CoV-2 being transmitted through sewage systems “is thought to be low.” While transmission of the virus through sewage may be possible, there is no evidence that has occurred.

County officials said Special Districts staff working in the treatment plants wear appropriate protective equipment to keep them safe.

Firms and universities researching sewage

Biobot told Lake County News they are working to reach as many communities as possible through their COVID-19 response program.

“Unfortunately, we cannot share which communities are involved at this time,” the company said.

While there are asymptomatic patients who are still infectious or patients with mild symptoms who are not captured in the limited testing data, sewage data is able to capture the whole population, so such samples enable public health interventions to match and better understand the actual infected population, the company said.

Besides using the sewage data to understand the scope of the outbreak independent from patient testing or hospital reporting, Biobot said a better understanding of scope offers more information for officials trying to determine public health interventions.

The company said the work could also help anticipate hospital capacity and readiness and give an early warning for the reemergence of the novel coronavirus if it has a seasonal cycle – like many are projecting that it does.

Besides Biobot and its partners, other organizations – particularly several universities – are working on wastewater testing to track COVID-19.

Researchers at Cranfield University in the United Kingdom said last month they are working on a new, quicker test to detect SARS-CoV-2 in the wastewater of communities infected with the virus.

The rapid test kits offer paper-based devices that could be used on-site at wastewater treatment plants to trace sources and determine whether there are potential COVID-19 carriers in local areas, the university said.

“If COVID-19 can be monitored in a community at an early stage through wastewater-based epidemiology, effective intervention can be taken as early as possible to restrict the movements of that local population, working to minimize the pathogen spread and threat to public health,” said Dr. Zhugen Yang, lecturer in sensor technology at Cranfield Water Science Institute.

Similarly, a research team from the University of Michigan and Stanford University has received a rapid response grant from the National Science Foundation that they’re using to study how the novel coronavirus behaves and moves through the environment, with a focus on wastewater detection.

Researchers said the work could provide a clearer picture of how broadly the disease is spreading because it could pick up evidence of upticks in more mild cases or those that bring no symptoms at all.

“For epidemiologists interested in the prevalence and incidence of COVID-19, our methodology offers an estimate that does not rely on testing every individual, nor is it as prone to measurement bias,” said Nasa Sinnott-Armstrong, a doctoral student at Stanford working on the project. “We could identify areas with rapidly increasing cases as a warning system to the health care system. Finally, these numbers can help epidemiologists model the trajectory of the pandemic with far less testing burden on our health care system.”

Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it. . Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.