Malignant catarrhal fever in a captive American bison (Bison bison) in Italy.

Malignant catarrhal fever (MCF) is a fatal, systemic disease of cattle and other domestic and wild ruminants that, in Europe, is caused by Ovine herpesvirus 2 (OvHV-2). American bison (Bison bison) are highly susceptible to the disease. An adult American bison, housed in a zoo in southern Italy in close cohabitation with a group of domestic sheep (Ovis aries aries) displayed clinical signs that resembled the acute form of MCF. By real-time polymerase chain reaction, OvHV-2 DNA was detected intravitam in blood, in nasal and ocular swabs, and postmortem in tissue samples of the bison. By indirect fluorescent antibody test, high MCF antibody titers were found in the bison serum. Ovine herpesvirus 2 DNA and antibodies were also found in blood samples from the domestic sheep, thus suggesting a potential role of these animals as a source of the infection. To the authors' knowledge, this is the first MCF case in captive ruminants in Italy and the second confirmed case in captive bison of European zoos.