http://www.cdc.gov/ncidod/dpd/parasites/Giardiasis/factsht_giardia.htm
Centers for Disease Control and Prevention, U.S. Department of Health and Human Services
Giardiasis, a diarrheal disease caused by the microscopic parasite Giardia, often affects children in child care settings and those who consume contaiminated water or food. Find tips on reducing your risk of illness at home and abroad.