Gothe et al.
Horses as sentinel for the circulation of flaviviruses in eastern-central Germany
Viruses. 2023;15(5):1108. doi:10.3390/v15051108

Infections and diseases caused by zoonotic vector-borne arboviruses from the Flaviviridae family, such as West Nile virus (WNV), Usutu virus (USUV) and TBE virus are increasing in eastern Germany (federal states of Saxony, Saxony-Anhalt and Brandenburg).

A seroprevalence study has been carried out in eastern Germany in a total of 1,232 horses between March and June 2022 using a commercial panflavivirus competitive enzyme-linked immunosorbent assay (cELISA) in order to detect antibodies directed against the envelope proteins of the three flaviviruses. 10.2% of the horses showed positive results in the cELISA.

40 horses (3.3%) had WNV neutralizing antibodies, and 5 horses (0.4%) were tested positive in an USUV neutralizing assay.

69 horses (5.6%) were positive in a TBE neutralizing assay. The highest rate of 15% was found in the district of Dahme-Spreewald, which is not an official TBE risk area based on the number of human cases, while in the district of Dessau-Rosslau, an official risk area, the seropositivity ratio was below-average. These results indicate that TBE virus infection in horses happen regularly in the studied area, even if the specific districts are not classified as official risk areas due to a low incidence in humans.

Higher age increased the likelihood of TBE seropositivity. None of the horses showed neurologic signs.

The study confirmed further evidence for the presence of WNV, USUV and TBE virus in eastern Germany. The authors concluded that horses are useful sentinels to determine flavivirus infections in eastern Germany.

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