A concentration technique for obtaining viable cysts of blastocystis hominis from faeces.

Blastocystis hominisis a common parasite implicated in a variety of intestinal problems. Oral-faecal route of transmission has been postulated but the cystic phase which is presumably the infective stage of the parasite, has only recently been described using electron microscope. However, little information is available on the light microscopic morphology of the cyst. There are two possible reasons for this. The first is the relatively small size of the cyst, as compared to some other intestinal protozoa and the difficulty in separating it from the non-cystic stages of the parasite. The concentration technique described in this paper ovemomes this problem and separates the cysts from the non-cystic stages, there by enabling its easy recognition in faecal samples.