Table 1.
Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) viral RNA in wastewater concentrates by RTqPCR and nPCR.
| SARS-CoV-2 RTqPCR (No. of Replicates) 1 |
Nested RT-PCR Gene Target (PCR Product Size) 2 |
Genome Sequenced (No. of Nucleotides) | ||||||
|---|---|---|---|---|---|---|---|---|
| Sampling Date |
RdRP Gene (log10 gc/L Sewage) |
E Gene (log10 gc/L Sewage) |
nsp2-PLPro Gene nPCR1 (714 nt) |
RdRP Gene nPCR2 (523 nt) |
RdRP Gene nPCR3 (527 nt) |
RdRP Gene nPCR4 (235 nt) |
ORF8b-N Gene nPCR5 (612 nt) |
|
| 14-Jan-20 | - | - | - | - | - | - | - | - |
| 11-Feb-20 | - | - | - | - | - | + | + | 847 |
| 11-Mar-20 | 4.84 ± 0.45 [4.18–5.52] (n = 10) |
4.98 ± 0.40 [4.63–5.41] (n = 3) |
+ | + | + | + | + | 2376 |
| 14-Apr-20 | 5.27 ± 0.30 [4.77–5.91] (n = 11) |
5.78 ± 0.07 [5.71–5.84] (n = 3) |
+ | + | + | + | + | 2376 |
| 12-May-20 | <3.5 (n = 11) 3 |
- | + | + | + | + | + | 2376 |
Wastewater samples were concentrated using a standard filtration–centrifugation method (concentration factor: 20–60×).1 Mean values of log10 SARS-CoV-2 genome copy (SC2 gc)/L wastewater with standard deviations are shown. 2 Dark grey indicates positive in at least 1/5 replicate nPCR reactions. Light grey indicates positive only after additional concentration (up to 500×). Positive PCR results were obtained for Feb–May samples in at least two independent concentration processes for at least two different gene targets. The January sample remained negative even after a second concentration step.3 Only 3/11 replicates gave positive RTqPCR signals with RdRP target, so viral RNA quantification was not possible.