COVID-19 infections are widely tested using nasal swabs. This method helped in identification of nearly 23 million infections around the world, India alone has reported 3.1 million infections.
Another mode of testing the prevalence of the virus is by testing the sewage generated from households.
Covid-19 has been detected in sewage waters around the world, in early 2020 when the virus spread was just picking up countries such as Italy, UK, India, Australia identified the virus strain in their raw sewage.
It was also reported that the virus traces were nil in the treated sewage water, giving a glimmer of hope towards curtailing its spread.
However, the problem arises for countries like India, Bangladesh and other countries with poor sewage treatment systems, where majority of the untreated sewage enters waterways, groundwater or disposed on land.
Water crisis and sewage system bottlenecks are not new, this pandemic is merely shedding light on its depth and severity
India generates nearly 62,000 MLD (Million Litres per Day) of sewage, of which just 38% is treated. Densely populated metropolitan cities (with population over 10 lakhs) in the country have just 51% treatment capacity .
An infected person excretes millions of virus genes into the sewage system through urine and stool. A researcher in UK identified the virus in human excreta nearly 33 days after testing negative for COVID-19 .
Virus laden untreated sewage makes its way into our pristine waterways creating a parallel pandemic for us in the near future.
In a recent study by CSIR-IIT and CCMB Hyderabad, identified COVID-19 RNA in the sewage sample collected from Sewage Treatment Plants (STPs) in the city.
They identified nearly 2 lakh citizens shedding the viral RNA into the system. It should be noted that only 40% of the sewage generated in Hyderabad is treated by STPs, making it challenging for researchers to estimate or help in surveillance of COVID-19 spread.
Identification and detection of COVID-19 in the sewage system helps track and set up a surveillance system to detect outbreaks and high incidence regions.
Many of the cases reported in India are asymptomatic or less in severity due to which the patient is often home quarantined, given the large density of population in India a sewage surveillance system will help identify crucial zones and catchments for containment.
This method of identifying outbreaks via sewage testing has been used for a long time, and most recently it was used for the SARS outbreak in 2002.
A study by IIT Gandhinagar in collaboration with Gujarat Pollution Control Board identified a jump in COVID-19 concentrations in the sewage from May 8th to May 27th, which correlated to the increases in cases identified (via nasal swab tests) in that given period .
Infection via sewage is yet to be determined, but it doesn’t negate the fact that there is a possibility of this happening. It has been identified that COVID-19 has a unique structure, making it behave differently in varied mediums.
Viruses similar to COVID-19 have been found to be active in the sewage system for upto 14days.
There is an urgent need for rigorous testing, analysis and cautionary steps to understand what this pandemic holds for us in terms of cross-infection, impact on marine animals and their behaviour in waterways.
Addressing this issue requires futuristic planning for large and small scale STPs which are well equipped to treat and eliminate pathogens, viruses such as COVID-19.
Scientists and researchers are racing against the clock to find vaccines or to understand the behaviour of the virus which has brought the whole world to a complete halt.
A cohesive, collaborative and rational approach to address the present and future problems is necessary with a scientific, political and administrative participation.
Dealing with the present issues is imperative before we are presented with a larger issue in the future.