Harderian gland involvement in facial lesions in the Mongolian gerbil.

Fourteen Mongolian gerbils with naturally occurring facial lesions were assigned randomly to 1 of 3 groups. The Harderian gland was removed surgically from the animals in group 1; a sham operation left the Harderian gland intact in animals in group 2; and animals in group 3 were housed on a sand substrate rather than the usual pine shavings. The progress of this disease state was monitored over a 2-month period. Animals in groups 1 and 3 recovered or improved, whereas the condition of the control animals worsened. It was concluded that the facial lesions are associated with an accumulation of the Harderian gland secretions around the external nares and that laboratory ambient temperatures and cage bedding may modify the development of the condition.