The Blastocystis ‘hominis’ parasite lives in the intestine of infected humans or animals (e.g., cats, dogs, pigs, horses, cattle). Millions of germs can be released in a bowel movement of an infected human or animal. Blastocystis ‘hominis’ is found on surfaces or in soil, food, or water that has been contaminated with the faeces from infected humans or animals. You can become infected after accidentally swallowing the parasite; you cannot become infected through contact with blood.  Accidentally swallowing Blastocystis ‘hominis’ picked up from surfaces (such as bathroom fixtures, changing tables, diaper pails, or toys) contaminated with faeces from an infected person or animal. Drinking water or using ice made from contaminated sources (e.g., lakes, streams, shallow [less than 50 feet] or poorly monitored or maintained wells). Swallowing recreational water contaminated with Blastocystis ‘hominis’. Recreational water includes water in swimming pools, water parks, hot tubs or spas, fountains, lakes, rivers, springs, ponds, or streams that can be contaminated with feces or sewage from humans or animals. Eating uncooked food contaminated with Blastocystis ‘hominis’. Having contact with someone who is ill with Blastocystosis. Travelling to countries where Blastocystosis is common and being exposed to the parasite as described in the bullets above. http://bhomcenter.org/wp/blastocystis-fact-sheet/