5 - Scatology Meets Arbovirology: Can Testing Wastewater Augment Traditional West Nile Virus Surveillance?

Early detection of impending outbreaks, prompt vector control, and public messaging can mitigate West Nile virus (WNV) outbreaks. However, human disease case reporting is subject to surveillance delays, and mosquito, dead bird surveillance, and virus testing are resource-intensive and thus limited in geographic scope. The National Wastewater Surveillance System (NWSS) currently has more than 250,000 unique wastewater samples and receives data from more than 1,500 sites in 50 states, Puerto Rico, USVI, Guam, and 6 tribal communities, representing more than 144 million people (40% of the US population). NWSS currently tests for SARS-CoV-2 and Mpox virus, and if expanded to include WNV, it could greatly augment ongoing WNV surveillance efforts. We have developed a novel WNV subgenomic flavivirus RNA (sfRNA) digital RT-PCR assay for use in wastewater surveillance. The subgenomic target is resistant to exoribonuclease activity, potentially increasing assay sensitivity from environmental samples. In spiked wastewater samples, WNV can be detected up to 72 hours in a dose-dependent manner. We will present results from wastewater samples collected in 2023 from areas experiencing human cases and outbreaks with concurrent mosquito surveillance programs to assess the feasibility and relative utility of this approach. If successful, pilot wastewater surveillance activities will be undertaken during the 2024 transmission season.