HYDERABAD: Hyderabad-based Centre for Cellular and Molecular Biology (CCMB), along with the Indian Institute of Chemical Technology (IICT), is collecting samples from various water bodies in the city to find out how many people are affected by Covid-19 and whose load is more for which virus variant. They are carrying out the study based on wastewater-based epidemiology (WBE).
During the first wave in August last year, the two institutions published a part of the ongoing study based on samples they had collected from different water bodies in the city, including Hussainsagar, Pedda Cheruvu (in Nacharam) and Nizam Talab.
The study had claimed that more than 6.6 lakh people in the city were already infected with Covid-19. These include symptomatic and asymptomatic individuals, as well as those who have recovered within the past 35 days. The study further aims to find out the extent of possible surge in Covid cases in the city and the number of people who have been affected by the new variant.
CCMB’s former director and current advisor Rakesh Mishra said: “The Coronavirus’ RNA is discharged through the faecal route from the human body. The fragment of the RNA that is present in the faecal matter is not infectious and is in an inactive state. However, analysing its presence in the city’s lakes, other water bodies, and Sewage Treatment Plants can help us in analysis. While our scientists were initially only focusing on STPs, it is an open secret that our city lakes are dumped with untreated sewage waste, so have also been collecting samples from lakes and other water bodies as well, to have a more conclusive report.”
The aim of the study is to find out the virus load of the new variant, “There are techniques being developed now through which we can say what per cent of which variant is present in the city. The water sample collected would contain faecal matter from lots of people. So, using a newly-developed technique, we will determine how many people have been affected by ‘A’ variant, how many by ‘B’ variant, and so on. The process is challenging, however, we are working on it,” Dr Mishra said. In this method, first, the water sample is collected. Then, RNA virus is isolated from the concentrated form of the samples. Once the RNA is collected, by using tests similar to the RT-PCR, we determine the presence of the virus, he added.
How to calculate
CCMB advisor Rakesh Mishra said that with how much virus could be shed through faecal matter in a day, the population of the city and based on the Cycle Threshold values, the number of people infected by the virus could be calculated