Morphology of Blastocystis sp. isolated from circus animals.

Blastocystis sp. is reported for the first time from faecal samples collected from a camel, a llama, a highland bull and a lion in a travelling circus. Fresh faecal specimens were examined by light and electron microscopy, and vacuolar and cyst forms of similar morphology were present in all three ungulates. These cells were smaller than cultured vacuolar cells of Blastocystis hominis isolated from humans and contained only a single vacuole in comparison to the multivacuolar cell found in fresh human faeces. The taxonomic relationship of Blastocystis isolated from humans and ungulates remains to be determined. The number of parasites present in the lion sample was too small to make valid comparisons.