Gambier Wastewater SARS-CoV-2
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
This model is experimental and updates frequently. For
questions or to receive regular updates:
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).
and Winter 2020
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.
a non-detect (failure to find virus) mean no virus is
Who is represented in
- 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
- It takes just
one unlucky breath to start a new cluster.
Will infected people get sick?
- 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
- The sample does
not include residences using septic fields, outside the
- 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
- Most people infected with SARS-CoV-2 experience no
symptoms, or mild symptoms. Their cases may or may not be
- 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
do the data come from?
samples (over the most recent 24-hour period) are obtained
from the Gambier Wastewater Treatment Plant on Monday and
- 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.
do virus levels show high variance?
composition varies with weather and inputs. The presence
of PCR inhibitors is variable.
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.
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).
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
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
- Masks prevent
infecting others and decrease the amount of virus that
reaches the wearer.