Causative agent: Demodex spp.
The species of demodex that causes demodecosis in bison has not been identified. Demodex mites invade hair follicles and sebaceous glands of the skin of animals, and man.
Clinical signs:
Demodecosis appears as small pus filled nodules, 7-9 mm in diameter, around the eyes, perineum and ventral aspect of the tail. It has also been associated with small but palpable lesions on the neck, flank and shoulders (48).
Diagnosis:
The nodules are easily visible around the eyes and perineal region. The pus from nodules may be examined under a microscope for the presence of the mite.
Treatment:
Demodecosis is of relatively minor significance in bison. Ivermectin has been show to be effective for the treatment of demodex mange in cattle(9).
Control:
Control programs for demodecosis in bison have not been reported and may not be required.