Emergence of Pediatric West Nile Virus Neuroinvasive Disease in Spain: An Expanding Threat in a Changing Climate—A Case Series

Background: West Nile virus (WNV) is an emerging zoonotic flavivirus that has caused outbreaks in Europe over the past 20 years. Approximately 80% of WNV infections are asymptomatic; clinical presentations include West Nile fever (20%) and WNV neuroinvasive disease (WNVND) (<1%), which can present as meningitis, encephalitis or flaccid paralysis. The clinical course of WNVND can be severe, with high morbidity (long-term neurologic sequelae) and mortality. No etiologic treatment is currently available, and management remains supportive. Methods: We conducted a retrospective description of all pediatric cases of WNVND reported in Spain to date. Results: Five cases of WNVND are described. Two patients presented with distinctive WNV encephalitis featuring extrapyramidal symptoms, 2 had WNV meningitis with complete recovery, and 1 developed WNV flaccid paralysis with severe long-term neurologic sequelae. Three cases were presented in 2020 and 2 in 2024. All cases were diagnosed during the WNV transmission season (July to September) and resided in the province of Seville. Conclusions: WNVND is a potentially severe disease with no etiologic treatment available. As WNV spreads, effective strategies for prevention, early detection and management are needed.