Giardiasis Attacks Intestine

During the summer every sip of water that I drink is from a stream. I am too much of a pansy to drink it without any type of purification (filter, chlorine, iodine, etc.). Several of my colleagues, however, are braver than me... or more idiotic... depending on your perspective.

They have experienced Giardiasis. Commonly known as the infection where "the bottom falls out of your world, and the world falls out of your bottom."

Giardiasis is a waterborne illness contracted by ingesting a microscopic parasite. It passes from the the feces of infected animals into the water, and because of its outer shell, remains intact until ingested by another animal.

Once infected, the parasite resides in the intestine. Giardia are flagellated protozoans that parasitize in the small intestine. In the stomach's acidic environment they begin excysting and become trophozoites. These attach to the intestinal mucosa by suction created from a ventral disk. This causes diarrhea and malabsorption by mechanisms that are not understood. The infection keeps you nautious and with diarrhea from 2 to 6 weeks, however you do not show symptoms of it for the first 14 days that it is incubating in your body.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=372844&tools=bot
http://www.dpd.cdc.gov/dpdx/HTML/Giardiasis.htm
http://www.cdc.gov/ncidod/dpd/parasites/giardiasis/factsht_giardia.htm#what