Fusiform erythrocytes resembling sickle cells in angora goats: light and electron microscopic observations.

Fresh blood from nine mature non-pregnant angora goats was found to contain a varying proportion of spindle-shaped, fusiform, triangular, pear-shaped, and other bizarre forms of erythrocytes in addition to normal discoid biconcave erythrocytes. The number of spindled and fusiform erythrocytes varied from 2 to 66 per cent, with two goats having such cells in excess of 50 per cent. Other aberrant forms of erythrocytes ranged from 3 to 54 per cent. Although the aberrant erythrocytes seemed to be present intravascularly, all goats studied were clinically normal and exhibited no other haematological abnormality. Light and electron microscopic observations indicated that polymerisation of haemoglobin in the form of longitudinal tubular fibres was responsible for conferring the fusiform and spindle shapes to erythrocytes, a phenomenon akin to that seen in sickle-shaped human and deer erythrocytes.