A 75-year-old male presented in August 2025 with acute confusion, left-sided weakness, unsteady gait, and right facial droop. Symptoms developed shortly after returning to Connecticut from a 2-week road trip from North Carolina to Colorado, during which he spent multiple days outdoors. He denied recent international travel. On presentation, he was febrile (39.5°C), prompting broad evaluation for infectious and neurologic causes.

Initial stroke workup, including non-contrast head CT and brain MRI, was negative. Empiric antimicrobial coverage with ceftriaxone, vancomycin, and acyclovir was initiated. An extensive infectious evaluation, including encephalopathy and tick-borne panels and viral PCR, was negative. Due to persistent left upper extremity weakness, MRI spine and brachial plexus imaging were obtained, revealing severe cervical spondylitic changes and findings concerning for possible brachial plexitis. He received intravenous Solu-Medrol with mild improvement in lower extremity strength, though arm weakness persisted.

Lumbar puncture showed lymphocytic pleocytosis and elevated protein, consistent with viral meningitis. WNV IgM and IgG antibodies were detected in cerebrospinal fluid, confirming neuroinvasive West Nile virus infection. Based on CDC surveillance data and travel history, the infection was likely acquired in Colorado, where elevated WNV activity was reported in 2025. The patient improved with supportive management and was discharged for outpatient follow-up.