France - A case of fatal encephalitis caused by a virus transmitted by pigeons (variant of Newcastle disease virus)

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A case of fatal encephalitis caused by a virus transmitted by pigeons​

Published on September 8, 2026 Updated on September 8, 2026 By Christophe Thomas

A person infected with a variant of Newcastle disease virus, which is widespread in pigeons, has died from encephalitis. This extremely rare case underscores the importance of monitoring pathogens circulating in animals.
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Newcastle disease virus, a very common virus in birds​

The avian influenza virus , which is actively circulating among birds and has also occasionally infected humans in recent months, is being closely monitored .

Another virus, less well-known to the general public, is Newcastle disease . This virus is very widespread among birds. The virulence of some of its strains, as well as its contagiousness among birds, makes it a notifiable disease. If a case is confirmed in a poultry farm, culling measures are implemented.

One variant of this virus, pigeon paramyxovirus type 1 (PPMV-1), circulates widely in pigeon populations worldwide. It can be transmitted to humans, but severe forms of infection are extremely rare. Until recently, only a few serious cases had been documented worldwide: fatal cases associated with respiratory syndromes and two deaths resulting from encephalitis.

A first death reported in France, and the first of a non-immunocompromised person.​

A collaborative study involving the Pasteur Institute, the AP-HP (Paris Public Hospitals), Necker-Enfants Malades Hospital, and ANSES (French Agency for Food, Environmental and Occupational Health & Safety) has just reported a third human death following encephalitis caused by PPMV-1. This is the first death in France and the first of a person who was not, a priori, immunocompromised. "The infectious agent was only identified after death, thanks to next-generation metagenomic sequencing performed on post-mortem tissue," explains Nolwenn Dheilly, head of the Pathogen Discovery Laboratory . The subsequent epidemiological investigation established that the PPMV-1 infection likely occurred during a shamanic workshop where the person may have come into contact with bird droppings.

Towards improved diagnosis for severe cases, which remain very rare​

Despite the description of this third death, it is important to emphasize that severe forms of the disease remain very rare. In the vast majority of cases, the virus causes mild conjunctivitis in humans, which resolves on its own. As for severe forms, they could be more easily diagnosed in the future. "Standard PCR tests using cerebrospinal fluid did not detect the virus. But PPMV-1 has been found in the lymph nodes. In order to detect the virus earlier, a lymph node biopsy, which is a minimally invasive procedure, could therefore be considered," explains Nolwenn Dheilly.

This study highlights the importance of health surveillance to identify viruses that are potentially pathogenic to humans and invites clinicians to consider PPMV-1 as a possible cause of encephalitis of unknown origin.

One Health Investigation into Fatal Encephalitis Caused by Pigeon Paramyxovirus Type 1, France, Emerging infectious diseases , May 2026

Nicolas Veyrenche1,2, Susana Boluda3,9, Philippe Pérot4,9, Isabelle Malissin5, Marianne Leruez-Ville1,2, Anne Jamet1, Agnès Ferroni1, Béatrice Regnault4, Maud Salmona6,7, Linda Feghoul5, Laurine Robert-Capraro4, Aurélie Leroux8, Béatrice Grasland8, Eric Niqueux8, François-Xavier Briand8, Isabelle Plu3, Danielle Seilhean3,10, Bruno Megarbane5,10, Jacques Fourgeaud1,2,10, Nolwenn M Dheilly4,10

1Necker-Enfants Malades Hospital, Paris, France

2Paris Cité University, FETUS, Paris

3APHP-Pitié-Salpêtrière Hospital, Sorbonne University, Paris

4Pasteur Institute, University of Paris, Paris

5Lariboisière Hospital, Paris Cité University, INSERM UMRS-1144, Paris

6Saint-Louis Hospital, APHP, Paris

7 Biology and Pathogenesis of Viral Infection team, INSERM UMR 1342, Saint Louis Research Institute, Université Paris-Cité, Paris

8Anses, Ploufragan-Plouzané-Niort Laboratory, Ploufragan, France

9These authors contributed equally to this article

10These senior authors contributed equally to this article.

Un cas d’encéphalite mortelle causée par un virus transmis par le pigeon | Pasteur.fr

Une personne infectée par un variant du virus de la maladie de Newcastle, très répandu chez les pigeons, est décédée des suites d’une encéphalite. Un cas extrêmement rare mais qui souligne l’importance de la surveillance des agents pathogènes circulant chez les animaux.

www.pasteur.fr