A microorganism in water that causes gastrointestinal illness in humans. It is commonly found in untreated surface water and can be removed by filtration. It is resistant to disinfectants such as chlorine. Cryptosporidium is a minuscule parasite that causes cryptosporidiosis which is a type of diarrheal disease. Each of the ailment and parasite are considered the primary types of Crypto. Animals are frequently polluted with various kinds of Cryptosporidium that are sometimes responsible for contaminating people as well. The parasite is equipped with an outside shell that allows it to reach long stretches of time and become highly receptive to chlorine treatment. While there are numerous manners in which these parasites can spread, water is unsurprisingly the most common form of spreading the parasite. Cryptosporidium is the primary origin of waterborne diseases among the U.S population.