Respiratory viruses like SARS-CoV-2, influenza, respiratory syncytial virus (RSV), and measles enter wastewater, or sewage, through the toilets and sinks of infected people. Monitoring respiratory viruses in sewage can provide an important early warning signal when someone in your sewershed (the area of town that drains into the wastewater treatment plant) sheds the virus.
The Kentucky Wastewater Surveillance System (KYWSS) is part of the National Wastewater Surveillance System (NWSS). KYWSS is nicknamed “Cues” in the same way the NWSS program is known as “News.” A cue is a signal for actors to start saying or doing something. Wastewater surveillance can provide ‘cues’ by tracking the virus before diseases like flu, Covid-19, RSV and/or measles are diagnosed in your community so people can do what they can to lower their risk of becoming ill.
The KYWSS is a whole-of-Kentucky effort supported by three divisions of the KY Dept for Public Health (KDPH): Public Health Protection & Safety (PHPS), Epidemiology & Health Planning (EHP) and the Division of Laboratory Services (DLS), as well as scientists at both the University of Kentucky (UK) and the University of Louisville (UofL). KYWSS sites include wastewater treatment plants (WWTPs) for regionally important sites such as university towns, military installations, tourism, and economic and medical hub cities to provide ample data for reliable wastewater-based sentinel epidemiologic data collection.
As part of the Centers for Disease Control and Prevention’s National Wastewater Surveillance System, KYWSS helps provide the public health infrastructure to monitor infectious diseases. Wastewater monitoring data can help identify outbreak trends early, direct prevention efforts to where they are most needed, and provide additional insights into disease spread that complement other public health surveillance data. Health departments, community leaders, and individuals can use wastewater monitoring data to make decisions about how best to protect their community.
How does this work?
A mechanical sampler automatically takes one sample hourly and then all 24 samples are combined to make the composite sample. Each site in the network collects a twenty-four (24) hour composite sample twice a week from influent before it enters a wastewater treatment plant (WWTP) The term 'influent' is used to describe the untreated wastewater that enters a wastewater treatment plant. Anywhere from ten thousand to hundreds of thousands of people’s plumbing drains to a single WWTP, and this preserves anonymity while actively monitoring respiratory viruses. Laboratories analyze samples by polymerase chain reaction (PCR), a technology that can identify specific viruses. By watching wastewater viral activity and comparing with trends in respiratory disease, we can prepare for increasing virus activity in our communities and control the spread of disease.
KYWSS regularly reports wastewater viral activity in Kentucky on its
public dashboard. The KYWSS dashboard displays Wastewater Viral Activity Level (WVAL) for COVID-19, Flu, and RSV and will be updated with additional features over time. KYWSS only collects and displays respiratory virus data. Dashboard maps display each collection site’s most recent WVAL as well as state and regional graphs showing a history of WVAL changes. To learn more about WVAL, visit the NWSS About the Data page.
Why is this important?
Monitoring viral activity in wastewater gives us the ability to identify changing infection trends for some viruses before those same changes in trends are seen in clinical cases. Wastewater monitoring data can help identify outbreak trends early, direct prevention efforts to where they are most needed, and provide additional insights into disease spread that complement other public health surveillance data. Health departments, community leaders, and individuals can use wastewater monitoring data to make decisions about how best to protect their community.
Compared to other surveillance systems, wastewater testing:
• Can be more cost and time efficient.
• Does not rely on availability of COVID-19 or other disease testing.
• Captures viral activity even when healthcare access is limited, or if an infected person does not seek healthcare when sick.
• Protects privacy since sewersheds capture all public sewer in a community; thousands to hundreds of thousands of households and commercial sites contribute to the sewershed.
Why is this ‘sentinel’ epidemiology?
Sentinel means early warning. Wastewater monitoring is fast and efficient. Wastewater data can show changes in disease trends before trends are seen in clinical cases. This information can be used to prepare health care providers and hospital systems for upcoming increases in visits and hospitalizations and can help communities take timely and effective preventive action.
From toilet flush to results only takes about five to seven days. KYWSS tests 24-hour composite samples taken twice a week from the combined sewage flow from the community served (sewershed) before it enters the treatment process at your local wastewater treatment plant (WWTP). This type of influent wastewater testing provides anonymized information on community-level disease trends for hundreds, thousands, even tens of thousands of people depending on the size of sewershed.
How does KYWSS protect my privacy?
Because each sewershed is comprised of thousands of households, schools, and businesses, detected viral fragments pose minimal ethical risks or threats to privacy. The Kentucky Wastewater Surveillance System will never sell or share influent samples with commercial third-party laboratories. KYWSS will never sell or share raw analytical data with commercial third-party laboratories. The KYWSS regularly monitors five (5) respiratory viruses: influenza A and influenza B (Flu A & B), respiratory syncytial virus (RSV), and SARS CoV-2 (Covid-19), and measles.
How will KYWSS use this data?
Wastewater can detect infection in a community before symptoms are apparent. Unlike other types of public health reporting, wastewater surveillance (monitoring) does not depend on people having access to healthcare, visiting a doctor when sick or availability of testing for an infection. Instead of identifying a specific individual with disease, the results show whether respiratory disease is increasing or decreasing for the entire population serviced by a particular WWTP. Wastewater signals can precede case reports by as much as 1-2 weeks. With this information, local health departments and healthcare providers can anticipate the potential for an outbreak or determine when an outbreak has passed.
The KYWSS dashboard shows wastewater detection of respiratory viruses in raw sewage. We use the WVAL calculations to show when levels of a virus in a community shift significantly up or down. Sometimes this means an outbreak is developing or resolving. Sometimes it can indicate the presence of an unexpectedly large flow of wastewater – for example, a large, multi-day basketball tournament, start of semester for a university, or holiday travel. In addition, individuals vary in the amount of respiratory virus that they shed in urine or stool; some people shed a lot, and others shed much smaller amounts even when sick. That is why the baseline (average) calculation (what’s ‘normal’) for the community associated with a given WWTP is so important to understanding viral activity.
Will KYWSS ever test for other things in wastewater?
KYWSS only tests for respirable diseases. Some states monitor monkey pox; Kentucky does not. Some sites in Kentucky independently submit samples for research to academic and commercial laboratories. WastewaterScan, for example, has been analyzing samples from Morris Forman WTQP in downtown Louisville for a number of years and that data is included in the weekly Louisville Metro Wastewater Update; it is part of a research project run by academics at Emory and Stanford Universities.
The KYWSS is managed by the Countermeasures Unit in the KDPH PHPS. This Unit has responsibilities for disaster preparedness, so we have organized participating sites within each of the five (5) Kentucky “Areas of Operation” (West, South, Central, Northern/Bluegrass, and East). In the event of a worrisome infectious disease outbreak, if requested by local communities or the Kentucky Department for Public Health, KYWSS may work with local governments and public health departments in cooperatively applying available wastewater surveillance technology to wastewater samples for improved disease detection and control.
How can I use the KYWSS dashboard?
Wastewater surveillance data are most useful when used with other surveillance data. When reviewed together, wastewater and other surveillance data can provide a more complete picture of disease spread within a community. The KYWSS Dashboard is designed to mirror the NWSS Dashboard while scaled to regions within the Commonwealth and individual sites. KDPH integrates early wastewater signals with later observed cases of disease with the intent of developing better predictions for outbreak potential. The KYWSS Dashboard compliments the Kentucky Respiratory Disease Dashboard to help Kentuckians track respiratory disease trends. Our hope is that this information will minimize respiratory virus-associated school and work closures and assist communities in optimally managing healthcare resources.
For questions regarding Kentucky Wastewater Surveillance System (KYWSS) or the KYWSS dashboard, please contact:
KYWSS@ky.gov
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