Final answer:
Cryptosporidiosis, caused by Cryptosporidium spp., can contaminate a large percentage of surface water in the U.S. It's transmitted via contaminated water, food, or direct contact, affecting areas with poor sanitation and necessitating water filtration to remove cysts.
Step-by-step explanation:
In the United States, cryptosporidiosis is an illness caused by the protozoan parasites Cryptosporidium parvum or C. hominis. These parasites are significant as they contaminate between 65-97% of the surface water, including public water supplies, water parks, swimming pools, and are a common cause of outbreaks when sanitation is compromised. The protozoan can be transmitted through contaminated water and food, as well as direct contact with infected animals or their feces. Children are particularly at risk, especially in settings such as day-care centers where the tendency to put objects in their mouths can lead to consumption of the resistant cyst stage of these parasites. Moreover, Cryptosporidium and similar pathogens such as Giardia have developed resistance to traditional chlorination treatments, necessitating that municipal water be filtered to remove these cysts and prevent waterborne diseases.