Testing of wastewater has detected increased COVID levels and even poliovirus. Can it anticipate future virus outbreaks?
When can we anticipate the next increase in COVID?
For months, the United States has documented more than 100,000 new COVID-19 cases and 300 deaths every day. In reality, the number of cases is likely substantially higher due to declining testing rates and the exclusion of positive home tests from official counts. With this many cases and new strains coming out, it seems likely that there will be more in the future.
Possibly in the coming weeks, when new, extremely contagious variants spread. Or perhaps in autumn and winter when we spend more time indoors. Or perhaps this virus will surprise us once more and wait until next year to reappear.
By the time we realise that COVID-19 infections are quickly spreading in a community, the pandemic has already been ongoing for some time. Because the first signs of the infection are often absent, it could spread for a while before anyone notices.
If we could predict when the next increase will occur, we might be able to take preventative actions. And this is where your stool comes in — faeces, poop, or whatever term you want — comes in.
Using wastewater to detect viral outbreaks
When a person has a viral infection, the virus can frequently be discovered in their faeces. Therefore, it is possible to test the wastewater of a town, city, or community for the presence of viruses and to determine the rate of increase over time.
This method has been utilised since the 1940s when polio was a significant threat. But testing wastewater can also find different kinds of hepatitis, the norovirus that causes flu-like symptoms, and maybe even measles.
The testing procedures for wastewater have evolved throughout time. In the beginning, people tried to grow viruses from water samples. More recently, they have been trying to find viral genetic material.
Polio and COVID were discovered in wastewater.
In June 2022, testing of London's wastewater detected the virus that causes polio, a potentially fatal or crippling disease. Even though no active cases of polio have been found in London yet, this discovery has led to a look into where the virus came from, who might be infected, and if it is a threat to public health.
In the United States, a county in New York that had been testing wastewater for COVID levels also began testing for polio after an unvaccinated adult contracted polio.
Has testing wastewater been beneficial for detecting and tracking SARS CoV2, the virus responsible for COVID-19? In fact, it has. Levels of this virus in wastewater have closely paralleled infection rates in numerous places around the world, and in some instances, have forecast an epidemic before a city has even observed an increase in cases. The CDC now regularly reports wastewater data alongside COVID-19 infection rates.
Typically, the results of wastewater testing are integrated with additional data such as infection rates reported by hospitals and doctors' offices, infection trends in neighbouring towns, and immunisation rates. This information offers public health officials a more complete understanding of a variety of concerning viral illnesses and where case counts may be headed.
How is wastewater data helpful?
Finding viruses in wastewater or a rise in the number of viruses in wastewater can help public health officials, doctors, and researchers.
Predict when a surge is occurring or at its peak, and then update messaging on preventative measures (for example, advice to wear a mask in public spaces or to physically distance yourself). They want more vaccinations and antiviral drugs. promote increased testing to detect novel variations.
Those who face barriers to testing, such as those without health insurance or a primary care physician, may find it particularly helpful to know if the number of cases in their neighbourhood is increasing. When there is a lot of undercounting, as is the case with COVID-19, testing wastewater can be very helpful.
Future improvements in wastewater testing may allow us to pinpoint the source of an outbreak in a single neighbourhood or a residential facility such as a nursing home or prison.
Sadly, the COVID-19 pandemic is still ongoing. And there are worrying warnings about the global spread of the virus that causes monkeypox. There is a good chance that viruses like polio and measles will come back and that new pandemics will happen in the future.
We will need as much assistance as possible to stay ahead of these outbreaks. Some of this assistance will probably come from wastewater. So, even though it might seem strange, what you flush down the toilet could help health officials find and maybe stop a threat to public health.
Photo by Polina Zimmerman