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Newly Emerged Shamonda Virus in Europe Associated with Neurological Disease in Horses, Switzerland 2026

  † These authors contributed equally to this work and share last authorship.

  ‡ Current address: PD Dr. med. vet. Lucia Unger, Institut Suisse de Médecine Equine (ISME), Vetsuisse Faculty, University of Bern, Länggassstrasse 124, CH-3012 Bern, Switzerland

Submitted:

01 October 2026

Posted:

05 October 2026

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Abstract
We report two cases of equine encephalomyelitis associated with the recently emerged European Shamonda virus type 1 (SHAV-EU1). Shamonda virus has not yet been described in horses but has caused an unprecedented outbreak in cattle in Western Europe this summer (2026). Both horses showed neurological deficits and lymphocytic cerebrospinal fluid pleocytosis associated with encephalomyelitis, vasculitis and hemorrhages in brain and spinal cord. Pan-Simbu RT-qPCR confirmed viral RNA in brain tissue, and Metatranscriptomic sequencing identified full-genome SHAV-EU1 sequences, proofing correlation to the outbreak in Swiss cattle.
Keywords: 
encephalitis
;  
vasculitis
;  
neurology
;  
horses
;  
Shamonda virus
;  
orthobunyavirus
;  
Switzerland
Subject: 
Biology and Life Sciences  -   Virology
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