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HIV & AIDS Health Center

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You Can Prevent Cryptosporidiosis

How Can I Protect Myself from Crypto? continued...

A. Boiling water: Boiling is the best extra measure to ensure that your water is free of crypto and other germs. Heating water at a rolling boil for 1 minute kills crypto, according to CDC (Centers for Disease Control and Prevention) and EPA (Environmental Protection Agency) scientists. After the boiled water cools, put it in a clean bottle or pitcher with a lid and store it in the refrigerator. Use the water for drinking, cooking, or making ice. Water bottles and ice trays should be cleaned with soap and water before use. Do not touch the inside of them after cleaning. If you can, clean water bottles and ice trays yourself.

B. Filtering tap water: Not all available home water filters remove crypto. All filters that have the words "reverse osmosis" on the label protect against crypto. Some other types also work, but not all filters that are supposed to remove objects 1 micron or larger from water are the same. Look for the words "absolute 1 micron." Some "1 micron" and most "nominal 1 micron" filters will not work against crypto. Also look for the words "Standard 53" and the words "cyst reduction" or "cyst removal" for an NSF-tested filter that works against crypto.

To find out if a particular filter removes crypto, contact NSF International (3475 Plymouth Road, P.O. Box 130140, Ann Arbor, MI 48113-0140; telephone 1-800-673-8010; fax 313- 769-0109), an independent testing group. Ask NSF for a list of "Standard 53 Cyst Filters." Check the model number on the filter you intend to buy to make sure it is exactly the same as the number on the NSF list. Look for the NSF trademark on filters, but be aware that NSF tests filters for many different things. Because NSF testing is expensive, many filters that may work against crypto have not been tested. Reverse osmosis filters work against crypto whether they have been tested by NSF or not. Many other filters not tested by NSF also work if they have an absolute pore size of 1 micron or smaller.

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