About the data

ABOUT DATASET

Provided by the Illinois Wastewater Surveillance System. This dataset is intended for public access and use.

This dataset includes raw data from an individual wastewater treatment plant for the viral target selected. Viral targets may include SARS-CoV-2, influenza A, influenza B, RSV, and others.

You can find answers to the most frequently asked questions in the FAQ section of our website, https://iwss.uillinois.edu/frequently-asked-questions/.

ATTRIBUTES

1. sars_cov_2: The concentration of the SARS-CoV-2 virus in gene copies per liter (gc/L).
2. influenza_a: The concentration of the SARS-CoV-2 virus in gene copies per liter (gc/L).
3. influenza_b: The concentration of the SARS-CoV-2 virus in gene copies per liter (gc/L).
4. sample_collect_date: The date the wastewater sample was collected.
5. method: A number that identifies if a sample was processed with a different method. I.e., samples with a “0” in this field were processed differently than samples with a “1” in this field.

NON-DETECTS, VALUES BELOW THE LIMIT OF DETECTION (LOD)

Each digital PCR (dPCR) assay has a limit of detection (LOD) specific to the target virus. Zeroes and non-zero values below the LOD should be treated the same, as non-detects because either no detectable virus was present in the sample or viral concentrations were so low that we do not have confidence that the result is reliable. This reduces the likelihood of false positives in the dataset.

The LODs for viral targets in this dataset are as follows:

• SARS-CoV-2: 4,080 gc/L
• Influenza A: 4,050 gc/L
• Influenza B: 7,575 gc/L
• RSV: 3,900 gc/L

For example, a sample tested for SARS-CoV-2 with a result of 3,725 gc/L would be considered a non-detect. When analyzing wastewater data, the Centers for Disease Control (CDC) recommends replacing non-detects with a value half of the assay detection limit (e.g., for SARS-CoV-2 half the LOD = 2,040 gc/L).

CONTACT

University of Illinois System, Discovery Partners Institute, iwss-admin@uillinois.edu