Benchmarking virus concentration methods for quantification of SARS-CoV-2 in raw wastewater

Area of Science:

• Environmental microbiology
• Virology
• Public health

Background:

• Wastewater-based epidemiology (WBE) is a cost-effective tool for monitoring public health, including SARS-CoV-2.
• Reliable SARS-CoV-2 detection in wastewater requires efficient virus concentration and suitable reference standards.

Purpose of the Study:

• To evaluate different wastewater concentration methods for SARS-CoV-2 RNA detection.
• To assess the suitability of external and internal reference viruses for WBE.

Main Methods:

• Collected wastewater samples from two European cities during the COVID-19 pandemic.
• Evaluated four concentration methods: two ultrafiltration variants and two adsorption/extraction methods.
• Assessed viral RNA recovery using RT-qPCR and tested external (bovine coronavirus) and internal (pepper mild mottle virus) reference viruses.

Main Results:

• A modified ultrafiltration method demonstrated significantly higher efficiency (p<0.01) and virus recovery.
• Ultracentrifugation was the only method to detect SARS-CoV-2 in wastewater from both cities.
• Pepper mild mottle virus proved to be a suitable internal reference standard.

Conclusions:

• Optimized ultrafiltration methods enhance SARS-CoV-2 detection in wastewater.
• Ultracentrifugation offers a reliable approach for municipal wastewater surveillance of SARS-CoV-2.
• Internal reference viruses are crucial for standardizing WBE methods.