CDC

West Nile virus dominated U.S. arboviral disease landscape in 2023

June 17, 2025

In 2023, the U.S. reported 2,770 human cases of nationally notifiable arboviral diseases, with West Nile virus (WNV) comprising a striking 95% (2,628 cases) of the total. Most cases occurred between July and September, and 73% required hospitalization. Notably, three WNV infections were transmitted via organ transplantation from two donors. Powassan virus was the second most reported arbovirus (49 cases), marking a continued rise from 2022. La Crosse virus emerged as the leading arboviral cause among children, with most pediatric cases classified as neuroinvasive. Overall, 208 deaths were reported, underscoring the severity of these infections. These findings highlight the need for clinicians to consider arboviral etiologies in patients presenting with acute febrile or neurologic illness during mosquito and tick seasons. Enhanced surveillance, personal protective measures, vector control, and rigorous screening of blood and organ donors remain critical to reducing arboviral disease burden.

Source:

Padda H, et al. (2025, June 12). MMWR Morb Mortal Wkly Rep. West Nile Virus and Other Nationally Notifiable Arboviral Diseases - United States, 2023. https://www.cdc.gov/mmwr/volumes/74/wr/mm7421a1.htm