Nearly 40% of transplant recipients who developed West Nile virus encephalitis following organ transplantation died, according to findings from a comprehensive new review, which also presents updated U.S. data on neuroinvasive disease and mortality trends, along with diagnostic and epidemiologic insights.
Researchers evaluated the epidemiology, transmission, clinical manifestations, and diagnostic considerations of West Nile virus (WNV) infection, emphasizing its status as the leading cause of mosquito-borne disease in the contiguous United States. Between 2014 and 2023, an average of 1298 neuroinvasive cases and 129 deaths were reported annually.
To conduct the review, investigators searched PubMed for English-language, full-text articles using the term “West Nile virus” from January 1, 2000, through May 9, 2025. The search returned 8117 articles, of which 95 were selected. These included 23 public health surveillance and investigation reports, 18 review articles, 11 observational studies, 11 case series/reports, and other epidemiologic data from the U.S. Centers for Disease Control and Prevention’s ArboNET system and international health agencies.
The findings indicated that approximately 80% of WNV infections are asymptomatic. About 20% result in West Nile fever, while less than 1% progress to neuroinvasive disease, including meningitis, encephalitis, or acute flaccid myelitis. Among patients with neuroinvasive disease, the overall mortality rate was 10%, increasing to 20% in individuals aged 70 years or older and up to 30%-40% in patients with hematologic malignancies or those receiving solid organ transplants or B-cell–depleting monoclonal antibodies. Severe long-term consequences were common, with 30%-40% of patients discharged to long-term care facilities and more than half experiencing persistent sequelae such as fatigue, myalgia, or cognitive impairment.
Among 14 documented clusters of organ transplant–related WNV transmission between 2002-2023, 32 recipients were infected, 75% of whom developed encephalitis. Of those, 38% died. Fourteen additional cases of transfusion-transmitted WNV have been reported since blood screening began in 2003. Diagnostic accuracy varied by immune status; reverse transcription–polymerase chain reaction (RT-PCR) testing demonstrated greater sensitivity than IgM serology in immunocompromised patients.
In the absence of approved therapies or vaccines, the authors emphasized the continued importance of prevention. Recommended strategies include Environmental Protection Agency–approved mosquito repellents, community-based mosquito control, and targeted public health messaging in high-incidence regions.
No conflicts of interest were reported.
Source: JAMA
