Wastewater surveillance of viruses has been done by the Tata Institute of Genetics and Society (TIGS), Bengaluru, in collaboration with the BBMP.
Viruses or pathogens enter wastewater through the stools of infected people. Scientists can test the sewage treatment plant (STP) samples for pathogens. (TIGS)
As Covid cases surged across the country in recent months, Karnataka reached its peak with the highest number of cases. Initially resembling a peak scenario at the end of December, Bengaluru’s wastewater surveillance now reveals a marked decline in viral loads within the sewage system.
Between 8 and 13 January, the positivity rate of SARS-CoV-2 from samples collected from wastewater across Bengaluru City was 96 percent. These samples were gathered from the bowels of 26 sewage treatment plants (STP).
Wastewater surveillance of viruses has been conducted by the Tata Institute of Genetics and Society (TIGS), Bengaluru, in collaboration with the BBMP.
Between 10 and 15 December 2023, the SARS-CoV-2 copies per ml were 2,000; however, in the last week of December, it increased to more than 3,000 copies per ml. Currently, it has decreased to less than 2,000 copies per ml in the current week’s data.
“Currently, the trends are pointing downwards, indicating that while the cases have not disappeared entirely, we are still detecting viral loads in the sewage system. Typically, after the peak, a decline in cases is expected. This decline is generally observed 4 to 6 weeks post-peak,” Director of TIGS Dr Rakesh Mishra told South First.
He further explained that during the festival period, when people gather and engage in close interactions, there is usually a rise in cases. “However, at present, the situation is showing a downward trajectory,” Dr Mishra said.
The surveillance shows the viral load of Covid 19 in the wastewater that comes from the households of the community. For more information about how it works, read here.
“Everything eventually comes out through the sewage system,” Mishra explained.
Viruses or pathogens enter wastewater through the stools of infected people. Scientists test the sewage treatment plant (STP) samples for pathogens.
“By testing, we know how many viral particles an infected person is shedding in a day. We also try to get the population size in the STP’s catchment area and estimate the RNA (Ribonucleic acid) fragments of the virus in the sewage system,” he said.
In a post on X, TIGS said that the real-time SARS-CoV-2 viral load in sewershed sites shows a sharp decline. “This doesn’t imply that the virus is instantly vanishing. As per government advisory, adhere to masking protocols, maintain personal hygiene, and avoid crowded places.”
#Realtime #SARSCoV2 viral load in sewershed sites #wastewaters – the viral load shows a sharp decline.
A caution – This doesn’t imply that the virus is instantly vanishing.
As per govt. advisory – adhere to masking protocols, maintain personal hygiene and avoid crowded places. pic.twitter.com/0DH2xRz0rl
— Tata Institute for Genetics and Society, India (@TIGS_India) January 15, 2024
Since late 2021, TIGS has been conducting wastewater surveillance in 26 STPs in Bengaluru, specifically to detect viral loads of Covid 19. They have now developed a surveillance system that can be implemented in other cities for identifying various pathogens.
“Environmental surveillance provides insights into real trends that may not be immediately apparent in the physical world. We plan to continue our Covid 19 surveillance for another year. This extended effort aims to establish a comprehensive surveillance system, encompassing a standardised operating procedure (SOP), locally developed technology, and a well-trained team. This system can subsequently be applied to monitor other pathogens such as avian or common flu, antimicrobial resistance (AMR), vector surveillance, etc. The goal is to create a versatile system that can be adapted for use in various cities to monitor sewage and safeguard public health,” said Dr Mishra.
On Monday, 15 January, India recorded 272 fresh cases of Covid, while the number of active cases of the infection has declined to 2,990, the Union Health Ministry said on its website.
No deaths have been reported in a span of 24 hours, according to the ministry’s data updated at 8 am.
Of the 272 new cases, Karnataka reported 113 cases, followed by Maharashtra at 64, and West Bengal at 25 between 14 January 8 am and 15 January 8 am.
The current number of active cases in the three states stand at 958 (Karnataka), 658 (Maharashtra), and 389 (Kerala).
Kerala, Tamil Nadu, Andhra Pradesh, Telangana have reported 22, 8, 4, and 3 new cases on Monday, respectively, with 356, 87, 77, and 35 active cases in these states.
India, overall, has reported 1,200+ cases of the JN.1 variant since November 2023, according to the Indian SARS-CoV-2 Genomics Consortium (INSACOG).
Karnataka has reported the highest number of JN.1 cases in India at 215 as of Monday, followed by Andhra Pradesh (189), Maharashtra (170), Kerala (154), West Bengal (96), Goa (90), Tamil Nadu (88), Gujarat (76), Goa (51), Telangana and Rajasthan (32), Chhattisgarh (25), Delhi (16), Uttar Pradesh (7), Haryana (5), Odisha (3), and Uttarakhand and Nagaland (1).
At the beginning of the year, INSACOG stated that seven out of 10 samples sent for genome sequencing are testing positive for the JN.1 variant of Covid-19.
Despite its ability to rapidly spread, the infection is milder and mostly asymptomatic. Information from across the world suggests that the cases are mild, with symptoms such as a cold, sore throat, low-grade fever (around 100 degrees Fahrenheit), body pain, weakness, and dry cough.
People are recovering quickly as these symptoms are generally manageable with symptomatic treatments like fever-reducing medication and pain relief.
While the WHO has classified JN.1 as a separate “variant of interest” due to its rapidly increasing spread, it poses a “low” global public health risk.
“The currently available data suggests that the JN.1 variant is neither leading to an exponential rise in new cases nor a surge in hospitalisation and mortality,” the sources stated.
The number of daily cases had dropped to double digits till 5 December 2023, but cases began to increase after the emergence of a new sub-variant — JN.1 — and cold weather conditions.
After 5 December 2023, a maximum of a single-day rise of 841 new cases was reported on 31 December 2023, which is 0.2 percent of the peak cases reported in May 2021, official sources said.
Of the total active cases, around 92 percent are recovering under home isolation.
India has witnessed three waves of Covid in the past with the peak incidence of daily new cases and deaths being reported during the delta wave during April-June 2021. At its peak, 414,188 new cases and 3915 deaths were reported on 7 May 2021.
The number of people who have recuperated from the disease stands at over 4.4 crore with a national recovery rate of 98.81 percent, according to the ministry’s data.
According to the data, 220.67 crore doses of COVID-19 vaccines have so far been administered in the country.
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