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Volume 31, Number 11—November 2025

Research Letter

Two Cases of Autochthonous West Nile Virus Encephalitis, Paris, France, 2025

Nolan Hassold-RugolinoComments to Author , Pierre Jaquet, Daniel Da Silva, Evangelina Papa, Julie Calmettes, Carole Henry, Hilaire Flamant, Etienne Brière, Guillaume André Durand, Gilda Grard, Ines Jabnoune, Nelly Fournet, Kamel Harchaou, Alexandre Bleibtreu, Michelle Saliba, Aude Gibelin, Marion Parisey, and Yacine Tandjaoui-Lambiotte
Author affiliation: Centre Hospitalier de Saint-Denis Hôpital Delafontaine, Saint-Denis, France (N. Hassold-Rugolino, P. Jaquet, D. Da Silva, E. Papa, J. Calmettes, C. Henry, H. Flamant, E. Brière, I. Janoune, M. Saliba, A. Gibelin, M. Parisey, Y. Tandjaoui-Labiotte); French Armed Forces Biomedical Research Institute, Valérie-André, Brétigny-sur-Orge, France (G.A. Durand, G. Grard); Aix-Marseille University, Marseille, France (G.A. Durand, G. Grard); Santé Publique France, Saint Maurice, France (N. Fournet); CHU Pitié-Salpêtrière, Paris, France (A. Bleibtreu)

Main Article

Table

Clinical characteristics for 2 cases of autochthonous West Nile virus, Paris, France*

Characteristics Patient 1 Patient 2
Age, y/sex
 64/M
 25/F
History of travel
 Portugal (2016), Jura (in eastern France) 3 weeks earlier
 None
Clinical manifestations
 Fever, headache, obnubilation, neck stiffness
 Fever, headache, peripheral facial paralysis, nystagmus, decreased reflexes in lower limbs, urinary retention
First lumbar puncture
Protein level, g/L (reference <0.40) 430 1,200
Leukocyte count, cells/L (reference <0.05)
 1.19; 76% neutrophils
 1.95; 90% lymphocytes
Second lumbar puncture, time after admission 4 d 72 h
Protein level, g/L (reference <0.40) 48 260
Leukocyte count, cells/L (reference <5)
 1.26; 88% lymphocytes
 1.4; 75% lymphocytes
Brain MRI
 Unremarkable
 Unremarkable
PCR WNV
 Positive in blood and CSF
 Positive in blood and CSF
IgM WNV Positive in blood and CSF Positive in blood and CSF

*CSF, cerebrospinal fluid; MRI, magnetic resonance imaging; WNV, West Nile virus.

Main Article

Page created: August 15, 2025
Page updated: August 20, 2025
Page reviewed: August 20, 2025
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