Shrimpy: My intent is not provoke arguments (which by the way are worthless) but there is little ground to argue against the infective nature of blastocystis - there are too many valid scientific citations to deny its pathogenic nature.
There once was argumentation concerning its pathogenic nature until the subtypes of blasto were found (blastocystis is a diverse or wide spectrum organism that has variations in which a large portion is not pathogenic but 11 subtypes have been identified as pathogenic)