Operationalizing SARS-CoV-2 wastewater monitoring to assess traveler health in Las Vegas, Nevada, USA

Objectives

This study explored expanded traveler- and tourism-focused wastewater monitoring in Las Vegas, Nevada, USA to complement community SARS-CoV-2 surveillance.

Methods

Wastewater samples were collected November 2023 to July 2024 from the largest community-scale wastewater treatment plant in Southern Nevada, USA (N = 112 samples) and two upstream utility access holes (i.e. manholes), isolating an international airport (N = 68 samples) and a commercial area with high-density bars and nightclubs (N = 30-33 samples). Polymerase chain reaction-based methods quantified RNA concentrations of SARS-CoV-2 and pepper mild mottle virus; whole genome sequencing characterized SARS-CoV-2 variants (N = 83 qualifying samples).

Results

SARS-CoV-2 concentrations exhibited concordance between liquids- and solids-based approaches. Similar trends were observed between methods and sampling locations; however, select manhole-level findings suggested potentially divergent COVID-19 infection profiles relative to residents. Whole genome sequencing also demonstrated similarities across sampling locations, although airport samples facilitated the identification of SARS-CoV-2 variants that either failed to spread locally (EG.6, JN.1.11) or preceded detection at the wastewater treatment plant (JN.1.7, KP.3).

Conclusions

These findings offer new insight into the operationalization of broader traveler- and tourism-focused wastewater monitoring, which may capture SARS-CoV-2 concentration spikes and genomic profiles in high-tourism/nightlife areas that community-scale sampling might otherwise miss.