Can blastocystis hominis penetrate water filters ?

Yes it can penetrate most common water filters found on the market in Australia. The water filter to choose to remove blastocystis hominis must be less than 1 micron absolute which includes reverse osmosis, rated by NSF for cyst removal, for more information see CDC’s fact sheet A Guide to Water Filters.

How can I remove blastocystis hominis from the water?

Heat the water to a rolling boil for at least 1 minute (at altitudes greater than 6,562 feet [>2,000 meters], boil water for 3 minutes).
Use a filter that has an absolute pore size of 1 micron or smaller, or one that has been NSF rated for “cyst removal.”
If you cannot heat the water to a rolling boil or use a recommended filter, then try chemically treating the water by chlorination or iodination. Using chemicals may be less effective than boiling or filtering because the amount of chemical required to make the water safe is highly dependent on the temperature, pH, and cloudiness of the water.

How do you get Blastocystosis and how is it spread?

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.

How can I prevent a Blastocystis ‘hominis’ infection?

Practice good hygiene
Avoid drinking water that might be contaminated
Do not drink untreated water from shallow wells, lakes, rivers, springs, ponds, and streams.
Do not drink untreated water or use ice made from untreated water during community-wide outbreaks of disease caused by contaminated drinking water.
Do not swallow recreational water. For more information on recreational water-related illness, visit CDC’s Health Swimming website.
Do not drink untreated water or use ice made from untreated drinking water in countries where the water supply might be unsafe.