Johne's disease in alpacas (Lama pacos) in Australia

Johne's disease was diagnosed in 10 alpacas (Lama pacos) in Australia between February 1993 and May 1994. Eight of the animals were between 12 and 24 months of age, one was a 6-year-old female, and one was a 4-year-old male. Five, including the 6-year-old and the 4-year-old alpacas, showed weight loss and diarrhoea before death or slaughter. The other cases showed no clinical signs of Johne's disease but 4 gave a positive result on faecal culture and one gave a positive result on testing with the caprine AGID assay and had acid-fast organisms in its faeces. At necropsy, all cases had grossly enlarged mesenteric lymph nodes. Johne's disease was diagnosed after histological examination of the lymph nodes with conventional culture and polymerase chain reaction testing of tissue samples. This report outlines the clinical, epidemiological, and pathological findings in these cases.