Gambier Wastewater Report

Gambier Wastewater SARS-CoV-2 Virus Report

The Village of Gambier and Kenyon College are sampling wastewater for levels of RNA from dead coronavirus SARS-CoV-2, the cause of COVID-19 disease. On-campus wastewater testing is funded by the Ohio Water Resources Center and Ohio Dept of Health.
This model is experimental and updates frequently. For questions or to receive regular updates: slonczewski [at] kenyon.edu

Winter and Spring 2021Wastewater SignalGambier

● Log2 concentration (doublings) of dead viral RNA per liter, reported by Source Molecular (LuminUltra). RNA levels from five Kenyon residential groups are scaled to population size.
COVID cases resident in Village of Gambier (including Kenyon College) on dates that tests were performed (Knox Public Health).

Fall and Winter 2020Wastewater SignalGambier

What do the virus levels mean?

  • Virus levels above 500 RNA per liter (29 = 512) indicate active infections in the Village.
  • The wastewater signal often appears two weeks before individual clinical tests are performed. This probably means that wastewater reveals earlier cases missed by clinical qPCR (false negative rate = 30%).
  • Wastewater can detect infectious cases before the individual experiences symptoms. Before symptoms, the infection may already have spread to others. Cases can be asymptomatic.
  • Mask and physical distancing can prevent their spread.
Virus spread time course

Does a non-detect (failure to find virus) mean no virus is present?

  • No, because failure of virus detection in one sample means that wastewater substances could have inhibited the lab reaction. Single cases may avoid detection.
  • Two or more non-detects suggest that virus levels are too low for detection.
  • It takes just one unlucky breath to start a new cluster.
Who is represented in the sample?
  • The Village sample (blue line) represents all individuals whose waste enters the Gambier wastewater treatment plant. This includes most village resident, employees at local businesses and Kenyon College, including all students on campus.
  • The sample does not include residences using septic fields, outside the wastewater system.
  • The total village population in August was estimated at 700 individuals, including 66 students. By September, the total was approximately 1,600 including an approximate number of 920 students on campus. Most students departed over the period November 23-December 6, leaving 66 students residing on campus. The village population in December 2020 was then about 700.
  • The NCAs sample (purple line) represents only the 66 students on campus through January.
Will infected people get sick?
  • Most people infected with SARS-CoV-2 experience no symptoms, or mild symptoms. Their cases may or may not be reported.
  • However people without symptoms may spread virus to others who get very sick.
  • Wearing a mask protects others--and protects you from getting large doses of virus that cause more severe illness.

Where do the data come from?

  • Composite samples (over the most recent 24-hour period) are obtained from the Gambier Wastewater Treatment Plant on Monday and Thursday mornings.
  • Samples are processed by Source Molecular (LuminUltra) laboratory, where virus RNA is amplified using CDC-approved primer sets N1 and N2.
  • Results are obtained within 4-6 days of the sample.
  • The data are interpreted by Kenyon faculty, in consultation with the OSU Water Resources Center, Ohio Department of Health and EPA collaboration for wastewater testing research.

Why do virus levels show high variance?

  • Wastewater composition varies with weather and inputs. The presence of PCR inhibitors is variable.
  • Different infected individuals shed different amounts of virus.
  • A single individual may infect many people at once, leading to a spike in signal that declines as cases resolve.
  • The rolling average removes much of the variance.

Why is there virus present when only occasional cases of illness are reported?

  • Some infected individuals show no symptoms yet they shed virus particles and can transmit infection. The relationship between reported and asymptomatic cases in a hypothetical community is illustrated in this diagram (illustration only, no data).

    Hypothetical Case Reports
    Hypothetical Undetected Cases

Is wastewater SARS-CoV-2 virus a danger to the community?

  • No, because the SARS-CoV-2 coronavirus in wastewater is dead virus. Only RNA pieces of dead virus are detected.
  • All wastewater is handled with PPE and shipped under regulated conditions.

What is happening to virus levels in the broader community?

  • Current virus levels are high throughout Ohio.
  • Mask wearing and physical distancing are the best ways to keep virus prevalence low.
  • Masks prevent infecting others and decrease the amount of virus that reaches the wearer.