Life Cycle: The life cycle of blastocystis remains poorly understood. Through experimentation done by Stenzel and Boreham (5), it has been suggested that binary fission is the only possible means of reproduction. The avacuolar cell, without a surface coat, is swallowed and travels to the intestines. As it travels through the intestines, it morphs into its multivacuolar form, which has a thick surface coat. The cyst develops beneath the coat, which then sloughs off. The cyst is the probable infectious agent, and the cycle begins again with ingestion of the cyst. Excystation, probably induced by stomach acids, changes the cyst back into the avacuolar cell without a surface coat found in the intestines in the beginning of the life cycle. An amoeboid form is thought to exist, but its place in the life cycle is not well known, and possibly arises from the avacuolar form.