Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, USA.
National Summer Undergraduate Research Program, University of Maryland, College Park, MD, USA.
Sci Rep. 2021 Nov 1;11(1):21368. doi: 10.1038/s41598-021-00853-y.
There is a need for wastewater based epidemiological (WBE) methods that integrate multiple, variously sized surveillance sites across geographic areas. We developed a novel indexing method, Melvin's Index, that provides a normalized and standardized metric of wastewater pathogen load for qPCR assays that is resilient to surveillance site variation. To demonstrate the utility of Melvin's Index, we used qRT-PCR to measure SARS-CoV-2 genomic RNA levels in influent wastewater from 19 municipal wastewater treatment facilities (WWTF's) of varying sizes and served populations across the state of Minnesota during the Summer of 2020. SARS-CoV-2 RNA was detected at each WWTF during the 20-week sampling period at a mean concentration of 8.5 × 10 genome copies/L (range 3.2 × 10-1.2 × 10 genome copies/L). Lag analysis of trends in Melvin's Index values and clinical COVID-19 cases showed that increases in indexed wastewater SARS-CoV-2 levels precede new clinical cases by 15-17 days at the statewide level and by up to 25 days at the regional/county level. Melvin's Index is a reliable WBE method and can be applied to both WWTFs that serve a wide range of population sizes and to large regions that are served by multiple WWTFs.
需要开发一种基于废水的流行病学（WBE）方法，该方法能够整合地理区域内多个不同规模的监测点。我们开发了一种新的索引方法，即 Melvin 指数，该方法为 qPCR 检测提供了一种标准化的废水中病原体负荷度量标准，能够抵抗监测点的变化。为了展示 Melvin 指数的实用性，我们使用 qRT-PCR 测量了 2020 年夏季明尼苏达州 19 个不同规模和服务人群的市政污水处理厂（WWTF）进水中 SARS-CoV-2 基因组 RNA 水平。在 20 周的采样期间，在每个 WWTF 中均检测到 SARS-CoV-2 RNA，平均浓度为 8.5×10 基因组拷贝/L（范围为 3.2×10-1.2×10 基因组拷贝/L）。Melvin 指数值和临床 COVID-19 病例趋势的滞后分析表明，在全州范围内，指数化废水中 SARS-CoV-2 水平的增加比新的临床病例提前 15-17 天，在区域/县一级提前 25 天。Melvin 指数是一种可靠的 WBE 方法，既适用于服务于广泛人群规模的 WWTF，也适用于由多个 WWTF 服务的大型区域。
