West Nile Neuroinvasive Disease: Case Series and Review of the Literature

Background: West Nile virus (WNV), although underdiagnosed, is the most common mosquito-borne disease and the second most common cause of viral encephalitis in the United States. Fewer than 1% of those infected develop neuroinvasive disease. Methods: We present a cluster of 3 cases of neuroinvasive WNV that occurred between August and September 2023 and a review of the literature for neurologic involvement with this virus. Data Sources: Sunrise Electronic Health Record; PubMed; Google; Division of Infectious Disease Diagnostics, Northwell Health Laboratories, Little Neck, NY. Results: The patients in all 3 cases were admitted with acute encephalopathy and other neurologic impairment. All 3 patients had a serum serologic diagnosis consistent with WNV. However, only one of 3 of the patients underwent a lumbar puncture with cerebrospinal fluid confirmation of WNV. Areas of Uncertainty: Clinical and laboratory guidelines have been described for the diagnosis of neuroinvasive WNV infection. This is especially important in patients who do not have cerebrospinal fluid confirmation. Conclusions: WNV is underdiagnosed. Furthermore, although neuroinvasive WNV infection is uncommon, this diagnosis should be considered in patients presenting with abnormal neurologic signs and symptoms during the summer months in geographic areas where potential transmission is of concern.