Cryptosporidium and Giardia: Waterborne Parasites

ryptosporidium and Giardia are single-celled, microscopic organisms and are disease-causing parasites that may infect people through contaminated drinking water and recreational waters. Symptoms resulting from infection include mild to severe diarrhea, abdominal cramps, weight loss, bloating, and vomiting. Chlorine, a commonly used disinfectant in water supplies, can eliminate Giardia from water sources, but may not eliminate Cryptosporidium. This publication describes these parasites and discusses them in terms of drinking water and the occurrence of waterborne disease outbreaks.