How does a person get this disease?
Giardiasis is easy to catch if you drink untreated water. Many animals carry giardia in their feces and may introduce this parasite into rivers, streams and springs in rural areas. Infected stream water may look clean and safe when it really isn't. City water may also be infected if sewer lines flood or leak. If you travel overseas, you may get giardiasis by drinking water (even tap water) that hasn't been boiled or treated.
Some people who get giardiasis don't become ill, but they may spread the parasite to other people. Giardiasis may be spread in day care centers if workers aren't careful to wash their hands each time after changing diapers.
Written by familydoctor.org editorial staff