Causative agent: Listeria monocytogenes
In cattle, L. monocytogenes causes encephalitis, abortion and septicemia (8). In bison, L. monocytogenes has been reported to cause abortions (8). The bacterium is very widespread in nature. L. monocytogenes is found in 46% of cattle manure samples and 82% of feed samples (9)
In cattle, stress may influence the occurrence of disease.
Clinical signs:
L. monocytogenes causes sporadic abortion in bison (8). Abortion usually occurs in the last trimester of pregnancy. In cattle, the incidence is low but has been as high as 15% (9).
Diagnosis:
To diagnose Listeria abortion an aborted fetus with placenta must be submitted to a diagnostic pathology laboratory for histopathology as well as bacterial culture and identification.
Treatment:
There have been no treatment protocols reported for the treatment of listeriosis in bison. Sick bison cows may be treated with long acting antibiotics.
Prevention:
There have been no control programs reported for listeriosis in bison (8).