West Nile Virus human cases in Türkiye in 2024

Human cases of West Nile Virus (WNV) infection have been reported since 2010 in Türkiye, with seasonal outbreaks occurring almost annually. Enhanced surveillance has been in place since 2011. The early detection of WNV infection is crucial for obtaining and delivering appropriate samples for accurate diagnosis, initiating proper treatment, conducting contact tracing and ensuring the early detection and control of outbreaks. This study aims to evaluate the increase in WNV cases reported in Türkiye in 2024, following a four-year period with no reported cases. All confirmed cases of WNV in individuals who were registered in the web-based Infectious Disease Surveillance and Early Warning System and Laboratory Information Management System between 1 January-31 December 2024 were retrospectively analysed. In 2024, there was a significant increase in the number of WNV cases in Türkiye, following a four-year period (2020-2023) during which no cases were reported. Between July and October, 133 cases and 13 deaths were reported. Most patients (58.6%; 78/133) were diagnosed with West Nile Neuroinvasive Disease (WNND). The mean age of cases was 60.4 (Median: 65, SD: ± 19.4 years, Min:7-Max:92) and 72.2% of cases were male. All cases were locally acquired. Most of the cases (47.4%; 63/133,) were residents of Istanbul. Raising awareness among clinicians and improving the diagnostic capacity of regional laboratories can ensure the rapid diagnosis and early detection of cases. Human WNV infection surveillance should be integrated with the surveillance of WNV in mosquito, birds and horses, as well as blood and organ transplantation surveillance. One Health approach should be adopted for surveillance, prevention and control measures.