Conze et al.
Tick-borne encephalitis virus (TBEV) infection in two horses.
Viruses. 2021; 13:1775. doi: 10.3390/v13091775

In some animals, infection (and seroconversion) by TBE virus occurs, but neurological disease is unknown or very rare. Among these animals are dogs, cats and horses. Recently an Austrian/German team has described two TBE cases in horses.

Case 1 is the first report of confirmed TBE virus infection causing fatal neurological disease in a horse in Germany. A 15-year-old Haflinger gelding in southern Bavaria had ataxia, behavioral changes and reduced consciousness. After neurological examination, the horse was tested for Borna disease virus and Borna disease was ruled out. The gelding was treated for encephalopathy of unknown cause but was euthanized after three days of hospitalization due to convulsive activity. A complete postmortem examination of the lymphocyte encephalomyelitis was carried out. Formalin-fixed paraffin-embedded tissue samples were positive by a pan-flavivirus PCR, and the probe was identified positive for the European subtype TBE virus.

Case 2 is a 9-year-old Arabian gelding in northeastern Austria with acute neurological gait anomalies. The horse was euthanized, and the brain analyzed in detail. Again, Borna disease was excluded. TBE virus infection was confirmed by RT-PCR.

By using established molecular diagnostic methods and a novel in situ hybridization technique to differentiate between regionally important diseases, two cases of TBE in horses could be diagnosed.

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