Research to determine the origin of the ``mysterious mutant strain'' of the new coronavirus found in sewage

As a result of checking and investigating sewage samples, the building where the outbreak originated was identified as a mutant strain of the new coronavirus of unknown origin that was found in sewage in 2022, and it was found to be a mutant strain that was born in the human body. A paper was published that found that.

Tracing the origin of SARS-CoV-2 omicron-like spike sequences detected in an urban sewershed: a targeted, longitudinal surveillance study of a cryptic wastewater lineage - The Lancet Microbe

https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(23)00372-5/

Mark Johnson, a virologist at the University of Missouri, published a paper in February 2022 in which he identified four types of mutant strains of the new coronavirus from sewage samples in New York.

Multiple ``mysterious mutant strains'' of the new coronavirus found in New York sewage - GIGAZINE

In January 2022, one month before publishing this paper, Johnson and his team detected the new coronavirus variant strain ``WI-CL-001'' in wastewater samples obtained from a sewage treatment facility in Wisconsin. discovered.

So Johnson and his colleagues collected wastewater samples from sewers and drains in Wisconsin. The virus concentration therein was measured by RT digital PCR, and in addition to RNA sequencing to determine the host species of the virus, the SARS-CoV-2 spike receptor binding domain and, if possible, the entire viral genome. were also sequenced to identify and characterize the evolution of this lineage.

As a result, it was determined that the source of WI-CL-001 was a single commercial building. High concentrations of WI-CL-001 were detected in the wastewater of this commercial building, and the majority of it was found to be of human origin.

Additionally, the research team generated more than 100 viral receptor binding domains and genome sequences from wastewater samples collected from January 2022 to January 2023 at this commercial building. This sequence included part of the base sequence characteristic of ``Pango strain B.1.234'', which was confirmed to be infected at low levels in Wisconsin from October 2020 to February 2021.

The research team claims that this shows that a single human infected with Pango strain B.1.234 is continuously shedding a mutant strain of the new coronavirus, and that the new coronavirus is infectious to humans. He argued that they mutate little by little and evolve.