Since the COVID-19 pandemic, the scope for wastewater-based epidemiology (WBE) has increased significantly and requires increasingly rapid, versatile and accurate detection methods to monitor the spread of disease.
Quantitative PCR has long been the standard for pathogen RNA detection in wastewater, but this technique can lack sensitivity and the ability to identify multiple pathogen variants in sewage. Droplet Digital PCR (ddPCR) can provide highly sensitive, absolute quantification in a single-step process for faster, more cost-effective WBE monitoring.
Download this infographic to learn more about
• How ddPCR can rapidly identify multiple pathogen variants in wastewater
• Achieving simple, quantitative data analysis, without the need for a standard curve
• Expert-designed assay kits to easily detect a range of pathogens
The Evolution of Wastewater-Based Epidemiology
Wastewater monitoring is a rapid, cost-effective and non-invasive method of tracking public health threats. Wastewater is a rich source of information, allowing
health agencies to easily monitor whole communities, regardless of income or access to healthcare. As the scope for wastewater-based epidemiology (WBE)
increases, versatile and accurate methods of detecting even low levels of pathogens are needed to predict outbreaks and limit spread.
Father of epidemiology, Dr Jon Snow first identifies
cholera as a waterborne disease. The handle of the
Broad Street water pump in London is removed, and
the outbreak abates.
1854
Researchers find a correlation between the
incidence of paralytic polio in the community and
high levels of poliovirus in sewage samples. 1
1940s
Dot blot hybridization methods are
developed to detect hepatitis A virus
in sewage-polluted waters. 2
1985
PCR enables more rapid, sensitive and efficient
detection of wastewater pathogens, and becomes
the new gold standard for WBE. 3
1990s
WBE technology is used to evaluate
illegal drug, alcohol and tobacco
consumption at a population level. 4
2000s
Early in the COVID-19 pandemic, SARS-CoV-2
RNA is discovered in untreated wastewater. WBE
is widely used to monitor the spread of the virus at
a community level and predict outbreaks. 5
2020
The widespread use of WBE during the COVID-19 pandemic
has brought these methods to the forefront of public health
surveillance. Appropriate infrastructure has been widely
established and other emerging or continued public health
threats can now be addressed e.g.,
Today
Antimicrobial
resistance
surveillance
Predicting and
preventing
epidemics
Tracking
chemical
exposures
Data down the drain
Wastewater data can be used to inform and implement public health
measures. Samples are collected from wastewater processing
plants and processed to detect and quantify microbial populations.
Wastewater
collection
Viral particle
concentration
RNA extraction
RNA detection
WBE
application
+
Surrogate
controls
Community
monitoring
Prevalence
estimation
Muddying the waters: the challenges of WBE
While quantitative PCR (qPCR) remains an important analytical tool for pathogen
RNA detection in wastewater, sewage samples pose multiple challenges for achieving
accurate and efficient results.
A more accurate approach
Droplet DigitalTM PCR (ddPCRTM) technology uses a water-emulsion droplet system to separate nucleic acid samples and
perform PCR amplification within each droplet. It enables absolute quantification of a target in a single-step process with multiple
advantages over standard qPCR.
Advantages of ddPCR
qPCR can lack sensitivity for
low viral copy numbers.
Sewage samples contain high
levels of lipids and proteins
that can interfere with qPCR
amplification steps.
Expert-designed solutions
Optimized ddPCR assays and kits are available
to detect a growing list of infectious pathogens in
wastewater samples, along with predesigned
assays to detect variants of concern:
1 Prepare ddPCR
reaction mix 2 Generate
droplets 3 PCR
amplification 4 Read droplets and
analyze results
References
1. Metcalf TG, Melnick JL, Estes MK. Environmental virology: from detection of virus in sewage and water by
isolation to identification by molecular biology—a trip of over 50 years. Annu Rev Microbiol. 1995;49(1):461-487.
doi:10.1146/annurev.mi.49.100195.002333
2. Jiang X, Estes MK, Metcalf TG. Detection of hepatitis A virus by hybridization with single-stranded RNA
probes. Appl Environ Microbiol. 1987;53(10):2487-2495. doi:10.1128/aem.53.10.2487-2495.1987
3. Toze S. PCR and the detection of microbial pathogens in water and wastewater. Water
Research. 1999;33(17):3545-3556. doi:10.1016/s0043-1354(99)00071-8
4. Huizer M, ter Laak TL, de Voogt P, van Wezel AP. Wastewater-based epidemiology for illicit drugs:
A critical review on global data. Water Research. 2021;207:117789. doi:10.1016/j.watres.2021.117789
5. Ahmed W, Angel N, Edson J, et al. First confirmed detection of SARS-COV-2 in untreated wastewater
in Australia: a proof of concept for the wastewater surveillance of COVID-19 in the community. Sci Total
Environ. 2020;728:138764. doi:10.1016/j.scitotenv.2020.138764
Public health
guidelines
implemented
qPCR can only provide
relative quantification
based on standard curves.
Surveillance of multiple
pathogens or variants is
limited by qPCR.
Less affected
by PCR
inhibiting
contaminants
Simpler data
analysis
Rapid
turnaorund,
results in <8h
Quantitative
without
requiring a
standard
curve
Allows
multiplexing
for different
pathogens or
variants
Smaller
sample
requirements,
reducing cost
Enrichment
of rare targets,
resulting in
increased
sensitivity
Channel 1 amplitude
Channel 2 amplitude
Template Primer(s) Probe(s) PCR mix
Mixture
Get a clearer picture of public health with ddPCR technology; discover solutions for wastewater-based epidemiology
PCR reagents and sample
are loaded into a multichannel
cartridge with droplet
generation mineral oil.
The droplet generator creates a
vacuum with negative pressure.
This divides the sample into
water-in-oil droplets.
The subsamples are
amplified by PCR.
The PCR plate is placed
into a droplet reader,
which analyzes each
droplet individually.
The story so far: for over 150 years, water has provided essential insights into infectious diseases
SARS-CoV-2
Adenovirus
Monkeypox
Norovirus
Respiratory syncytial
virus
Legionella pneumophila
Enterococcus
https://www.bio-rad.com/en-us/feature/wastewater-partner-epidemiology
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1128/aem.53.10.2487-2495.1987 https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.scitotenv.2020.138764
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1146/annurev.mi.49.100195.002333
https://doi.org/10.1128/aem.53.10.2487-2495.1987
https://doi.org/10.1128/aem.53.10.2487-2495.1987
https://doi.org/10.1128/aem.53.10.2487-2495.1987
https://doi.org/10.1128/aem.53.10.2487-2495.1987
https://doi.org/10.1128/aem.53.10.2487-2495.1987
https://doi.org/10.1128/aem.53.10.2487-2495.1987
https://doi.org/10.1128/aem.53.10.2487-2495.1987
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://www.sciencedirect.com/science/article/abs/pii/S0043135499000718?via%3Dihub
https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.watres.2021.117789
https://doi.org/10.1016/j.scitotenv.2020.138764
https://doi.org/10.1016/j.scitotenv.2020.138764
https://doi.org/10.1016/j.scitotenv.2020.138764
https://doi.org/10.1016/j.scitotenv.2020.138764
https://doi.org/10.1016/j.scitotenv.2020.138764
https://doi.org/10.1016/j.scitotenv.2020.138764
https://doi.org/10.1016/j.scitotenv.2020.138764