PUNE The city-based National Chemical Laboratories (NCL) that studied the sewer and drainage outlets of SARS-CoV-2 samples for detection and genome sequencing had reported the first mutation in the Omicron variant to from a sample collected in November of last year from its own wastewater treatment plant (STP).
Through drainage samples, the lab is helping the civic body identify areas reporting an early wave of Omicron cases, which can help further plan for isolation and containment areas.
Studying samples through sewage as the virus sheds from the body system by excretion, then through drainage and sewage, may allow earlier detection of samples, as most RT-PCR samples do not are tested only after reporting symptoms or after close contact.
Dr Ashish Lele, Director of NCL, said: “Studying wastewater in the population helps understand various viruses that may be circulating in the community and can also help understand diseases like polio that are believed to be eradicated. This helps in earlier detection because the virus can start to dissipate even before the person starts showing symptoms and therefore helps in early detection. However, it also depends on several factors such as floating population, migration and others.
The NCL reported the first mutation of the Omicron strain based on a sample from its own wastewater treatment plant (STP) at the NCL-Phytorid plant which had a high viral load when the sample was collected on November 22, 2021. The sample shows a mutation in the Omicron variant.
The sample shows Omicron a week before the institute reports the first case of the Omicron variant in swab samples, in the first week of December 2021.
The institute had also reported one to two mutations in the Omicron variant which was specifically reported in the Vitthalwadi creek on samples taken on November 26, Bopodi creek on November 30, and Erandwane creek on December 3.
The institute had also reported a peak gene mutation in the Delta variant from samples collected between October and December 2021. The institute’s study also clearly indicated that the viral load in the January samples is much higher. higher than those found in October, November or December of last year. STP samples are studied from 30 channels and drains as well as 12 STPs and each sample is studied approximately twice per week.
However, clarifying the mutation, Dr Lele said: “Mutations are a natural process and this should not be alarming as mutations are not of concern. We found that most of the strains are similar to those already published and only a few minor mutations are noted, which is not of concern and requires further study.
“We study the wastewater samples and send the report to the city body every week to help them plan for containment or monitoring accordingly,” he said.