Abstract:
A 4-year-old East African black headed ewe was presented to Sokoine University of Agriculture Animal Hospital with a
history of loss of body condition and respiratory distress. Clinical examination revealed poor body condition, severe
leukopenia with neutrophilia and lymphopenia. Radiographic examination of the thorax revealed an elongated caudal
mediastinal mass with soft tissue opacity dorsal to caudal vena cava and caudal to the carina. The ewe was humanely
euthanised due to deteriorated body condition. At post-mortem examination the mass contained caseous creamy material
with early laminated appearance surrounded by a whitish fibrous capsule suggestive of chronic abscessation of caudal
mediastinal lymph node. Corynebacterium pseudotuberculosis was isolated on bacterial culture of pus sample. A
diagnosis of an abscessed caudal mediastinal lymph node as a result of Corynebacterium pseudotuberculosis infection
was made. Thoracic radiography should be considered in sheep with chronic progressive emaciation and respiratory
distress. Further, in sheep with caudal mediastinal mass, caseous lymphadenitis should be considered as one of the
differential diagnoses.
