The COVID-19 pandemic is now in its third year and scientists and policymakers are in a race across the world to try to stay a step ahead of the virus.
A section of those tracking COVID-19 are doing so by studying our sewers – human faeces in the sewers to be precise.
The most well-known way of shedding the virus is through your nose or mouth when you are coughing, sneezing, or even exhaling. However, people also shed the virus when they use the toilet. They shed the virus in faeces for a longer duration of time.
“Regularly analysing wastewater from sewage treatment plants allows scientists to measure when those levels are rising or falling and what variants are present about four to five days before people start testing positive,” notes a piece in The Washington Post.
Wastewater analysis for disease-tracking is not new
The tracking of diseases through wastewater – called wastewater-based epidemiology – was first proposed over 70 years ago as a way to track polio virus. It has since been used to track the exposure of pollutants in human populations and even drug consumption within cities.
As for COVID-19, 58 countries have established a wastewater testing process, according to a Forbes report. Several of these countries publicly share the data they collect through a platform named COVIDPoops19.
The idea behind such a mechanism is to produce regional, community-level anonymous data for public health purposes that gives an idea about the prevalence of a disease in a wider population.
What benefits have been seen from sewer-tracking?
In the US, hospitals have been put on alert in advance in anticipation of a rise in patients based on observations of increased coronavirus presence in wastewater.
There have been instances, such as one cited by The Washington Post in the American city of Houston, where a recently-observed high viral presence in wastewater did not accompany an increase in hospitalisations. This suggests that public immunity from vaccines and previous infections is getting high in the region – people are catching the virus but are not falling sick.
Such a trend is a step closer towards what people have called “living with the virus”.
Tracking faeces in India gave scientists unique insight
Most of the focus in the last two years have been on masking to protect against virus-shedding in the air and hand-hygiene so that the virus doesn’t stick to our hands.
However, a study by India’s National Institute of Virology made scientists conclude that there is a high possibility of COVID-19 outbreaks in poor areas in developing countries through faecal matter. They found that people shed the virus in faeces for weeks after testing negative for the virus.
This creates a possibility of infections through contact with faecal matter in developing countries where patients are asymptomatically infected as they stay in crowded places and slums, according to the study published last month. This transmission may take place through either oral contact or airborne contact as faecal matter could also be aerosolised.
Therefore, proper toilets and maintenance of drains needs to be part of COVID-19 management, particularly in the developing world.
