Morphology of Blastocystis sp. from domestic birds.

A study of Blastocystis sp. from domestic birds was undertaken to determine if morphological differences occurred. Fresh faecal material from domestic chickens, ducks and geese and from commercially farmed ostriches was obtained. Blastocystis sp. from chickens was morphologically very different from that from the other hosts, having within the nucleus discrete spots of chromatin rather than a crescentic band (ducks and geese) or an elliptical band (ostrich). A thick surface coat surrounded all Blastocystis sp. cells in the faecal material, with isolates from the ostrich having the thickest surface coat relative to the cell diameter. Cysts were more commonly found in the chicken samples but were also detected in the duck and ostrich samples. This study suggests that three morphologically distinct groups are represented: one in the chicken, one in the ostrich and another in ducks and geese. These tentative conclusions require confirmation by molecular techniques.