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Volume 32, Number 5—May 2026

Dispatch

One Health Investigation into Fatal Encephalitis Caused by Pigeon Paramyxovirus Type 1, France

Nicolas Veyrenche, Susana Boluda1, Philippe Pérot1, Isabelle Malissin, Marianne Leruez-Ville, Anne Jamet, Agnès Ferroni, Béatrice Regnault, Maud Salmona, Linda Feghoul, Laurine Robert-Capraro, Aurélie Leroux, Béatrice Grasland, Eric Niqueux, François-Xavier Briand, Isabelle Plu, Danielle Seilhean2, Bruno Megarbane2, Jacques Fourgeaud2, and Nolwenn M. Dheilly2Comments to Author 
Author affiliation: Hôpital Necker-Enfants malades, Paris, France (N. Veyrenche, M. Leruez-Ville, A. Jamet, A. Ferroni, J. Fourgeaud); Université Paris Cité, FETUS, Paris (N. Veyrenche, M. Leruez-Ville, J. Fourgeaud); APHP-Hôpital de la Pitié-Salpêtrière, Sorbonne Université, Paris (S. Boluda, I. Plu, D. Seilhean); Institut Pasteur, Université de Paris, Paris (P. Pérot, B. Regnault, L. Robert-Capraro, N.M. Dheilly); Lariboisière Hospital, Paris Cité University, INSERM UMRS-1144, Paris (I. Malissin, L. Feghoul, B. Megarbane); Saint-Louis Hospital, APHP, Paris (M. Salmona); Biology and Pathogenesis of Viral Infection team, INSERM UMR 1342, Saint Louis Research Institute, Université Paris-Cité, Paris (M. Salmona); Anses, Ploufragan-Plouzané-Niort Laboratory, Ploufragan, France (A. Leroux, B. Grasland, E. Niqueux, F.-X. Briand)

Main Article

Figure 1

Electroencephalogram (EEG) and brain magnetic resonance imaging (MRI) testing of a patient with encephalitis caused by pigeon paramyxovirus type 1, France. A) The first EEG (day 5 after hospitalization) revealed nonspecific encephalopathy consisting of disorganized theta background rhythm and right temporal rhythmic delta focalization without seizure. B) A later EEG (day 23 after hospitalization) confirmed severe encephalitis with continuous, diffuse, nonreactive, high-amplitude, delta rhythm background of pseudo-periodic delta biphasic and triphasic waves, suggestive of cortical necrosis. C) MRI revealed diffuse bilateral fluid-attenuated inversion recovery hyperintensities, primarily cortical, with subcortical extensions, particularly to the temporal and insular regions, involving the pulvinar nuclei of the thalami, the basal ganglia, the internal capsule, the limbic system, and cerebellum. D, E) Hypersignals in diffusion-weighted images (D) and with reduced apparent diffusion coefficient (E) suggested diffuse cytotoxic brain edema in relation to severe necrotic encephalitis.

Figure 1. Electroencephalogram (EEG) and brain magnetic resonance imaging (MRI) testing of a patient with encephalitis caused by pigeon paramyxovirus type 1, France. A) The first EEG (day 5 after hospitalization) revealed nonspecific encephalopathy consisting of disorganized theta background rhythm and right temporal rhythmic delta focalization without seizure. B) A later EEG (day 23 after hospitalization) confirmed severe encephalitis with continuous, diffuse, nonreactive, high-amplitude, delta rhythm background of pseudo-periodic delta biphasic and triphasic waves, suggestive of cortical necrosis. C) MRI revealed diffuse bilateral fluid-attenuated inversion recovery hyperintensities, primarily cortical, with subcortical extensions, particularly to the temporal and insular regions, involving the pulvinar nuclei of the thalami, the basal ganglia, the internal capsule, the limbic system, and cerebellum. D, E) Hypersignals in diffusion-weighted images (D) and with reduced apparent diffusion coefficient (E) suggested diffuse cytotoxic brain edema in relation to severe necrotic encephalitis.

Main Article

1These authors contributed equally to this article.

2These senior authors contributed equally to this article.

Page created: March 31, 2026
Page updated: May 07, 2026
Page reviewed: May 07, 2026
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