Multinucleate erythrocytes in a brown kiwi (Apteryx mantelli)

A 9-month-old brown kiwi had a history of 4 months of chronic anaemia, and failure to gain weight over the previous month. Haemograms taken at 4 and 5 months of age demonstrated a mild to moderate regenerative anaemia, and showed many erythrocytes had multiple nuclei, and nuclear fragments. On clinical examination, the kiwi was in moderate body condition and had pale mucous membranes. Haemograms on admission and 3 weeks later demonstrated the persistence of large numbers of bi- to multi-nucleate erythrocytes. Examination of bone marrow revealed the abnormality appeared in the later stages of maturation of erythrocytes, i.e. in the polychromatophil reticulocytes and mature erythrocytes, and did not appear in the erythrocytic precursors. Concentrations of lead, zinc, and folate in blood were unremarkable, and PCR testing for Plasmodium and Leucocytozoon spp. was negative. Electron microscopy of erythrocytes from the affected kiwi and a control kiwi showed an apparent maturation defect of the nuclear membrane in the affected kiwi. As the kiwi is still alive 17 months post-discharge, erythroid leukaemia is an unlikely diagnosis.