To investigate the concentration and genetic variations of SARS-CoV-2 in sewage in Guiyang city from February to December 2023.
A total of 1 034 sewage samples were analyzed for ORF1ab and N gene concentrations using quantitative PCR, and full viral genome sequencing was performed using the Illumina sequencing platform.
Among the 1 034 samples collected, 587 were tested positive for SARS-CoV-2. The median concentration of the ORF1ab gene was 3.69 copies/ml, and the median concentration of the N gene was 7.57 copies/ml. There was a correlation between the concentration of SARS-CoV-2 in sewage and the number of reported cases from medical institutions. Full genome sequencing was conducted on five SARS-CoV-2 positive samples with CT values <32, achieving an average coverage ranging from 63.91% to 97.28%. All viral types identified were Omicron sub lineages, with a total of 110 mutation sites identified. The S protein exhibited 22 amino acid changes, including the critical mutation E484A.
The detection rate of SARS-CoV-2 in urban sewage in Guiyang city is relatively high, and the viral concentration correlates well with clinical cases. The application of whole genome sequencing technology allows for the detection of genetic variants in the viral material present in sewage and identifies multiple mutation sites. Monitoring viruses in urban sewage effectively captures the spatiotemporal trends of the disease, serving as an important complement to clinical testing and providing a reference for local governments to implement precise epidemic prevention policies.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |