MORPHOLOGICAL DIFFERENCES IN BLASTOCYSTIS CYSTS - AN INDICATION OF DIFFERENT SPECIES

Cyst forms of Blastocystis that show disparate morphology in relation to the previously described cysts were detected in faecal material fro m animal hosts. Transmission electron microscopy was performed without attempts to isolate or concentrate Blastocystis from the faecal mater ial. Large, multinucleate cyst forms were found in faecal material fro m Macaca monkeys. These cyst forms measured up to approximately 15 mu m in diameter and were often larger than vacuolar forms present in the same samples. Four or more nuclei were frequently seen in the cysts. Multiple individual cysts enclosed by a single fibrillar layer were fo und in faecal material from domestic chickens. Each individual cyst wi thin the multiple cyst form measured approximately 3-4 mu m in diamete r and appeared to be uninucleate.