Laboratory Assessment of Wastewater as Surveillance Tool for West Nile Virus, United States

West Nile virus (WNV) is the most common cause of domestic human arboviral infection in the contiguous United States. WNV surveillance across the United States is not comprehensive and is limited. Nonclinical WNV surveillance is variable, and WNV surveillance in humans is limited by the percentage of symptomatic human infections and time it takes to seek healthcare and diagnosis. Wastewater surveillance has been used to detect viruses shed from asymptomatic and symptomatic persons; therefore, we assessed wastewater as a surveillance tool for WNV tracking. We tested archived RNA and raw wastewater from 6 states with documented human illness during the 2023 WNV transmission season for WNV RNA. WNV RNA was detected in 18% (n = 29/158) of samples from Arizona, California, Colorado, Illinois, Indiana, and Nebraska. Our results highlight the ability to detect WNV in wastewater and the potential of wastewater surveillance to augment current surveillance data.