Giardiasis (or giardiosis) and cryptosporidiosis are intestinal infections caused by protozoan parasites (giardia lamblia and cryptosporidium parvum). While giardiasis is often mild, cryptosporidiosis is a serious intestinal disease. These conditions are often caused by ingesting water or food contaminated with the feces of infected animals or humans. Symptoms of giardiasis and cryptosporidiosis may include diarrhea, gas, nausea and cramps. Parasites are typically found in outdoor water sources such as lakes, streams and pools. Black Berkey purification elements remove cryptosporidium by over 99.996% and have been tested to reduce Giardia cysts by over 99.994% as confirmed by test results.