Vienna’s Schönbrunn Zoo will not be housing or displaying bison for the foreseeable future after five of the animals died, likely due to a rare sheep herpes virus.

“At this stage, we assume there will be no bison at our zoo in the coming years. We’re still in the process of deciding what will become of the enclosure,” a zoo spokesperson told ORF.

The bison deaths, which took place over recent weeks, prompted an immediate investigation. Initial pathology reports pointed to infection with a sheep herpes virus, which is not transmissible to humans.

The virus has not caused any other animal deaths or illness at the zoo, according to the spokesperson, who added, “Aside from the bison, no other animals in the zoo have died due to the virus, nor have there been any other cases of illness.”

The zoo’s Ouessant sheep, formerly part of the petting zoo, were identified as potential carriers. These sheep can carry the virus without showing symptoms and are capable of spreading it to bison and other cattle.

To reduce the risk of further infections, Schönbrunn Zoo relocated all its Ouessant sheep to private holdings, confirming that “all 13 Ouessant sheep have already been relocated to private sheep farms.”

It remains uncertain whether the zoo will reintroduce bison in the future, as officials consider alternative uses for the now-vacant enclosure.