Detection of Shamonda Virus in Two Horses with Neurological Signs in Germany

Shamonda virus (SHAV), which has recently emerged in Central Europe and has caused disease in numerous cattle herds, was detected in brain tissue from two horses that showed clinical signs, including neurological disorder, and underwent pathological examination. The horses reportedly exhibited seizure-like episodes (Horse A) as well as fever and ataxia (Horse B). In both horses, severe lymphohistiocytic meningoencephalitis with hemorrhages was observed in various parts of the central nervous system (CNS), while outside the CNS no abnormalities were found. The virus genome could be detected by RT-qPCR in all examined parts of the CNS of both horses. In a postmortem cerebrospinal fluid sample of one horse, the virus could only be detected with a very low genome load; however, postmortem contamination cannot be completely ruled out. Consistent with the histological findings, no SHAV genome was detected in either the blood or organs outside the CNS. Postmortem, CNS material-especially brainstem tissue-is suitable for detection of histological lesions and virus genomes via RT-qPCR, while intravital diagnostics of a SHAV infection in horses exhibiting neurological signs is at the moment only possible to a very limited extent. The epidemiological role of horses in the SHAV outbreak is currently unclear.