Caused by drinking water contaminated by human and/or animal feces (presumably including a beaver's), the symptoms of the ailment otherwise known as Giardia include loss of appetite, lethargy, fever, explosive diarrhea, loose or watery stool, stomach cramps, upset stomach, bloating, and flatulence. See also Animals.

Comments
Wasn't this also the name of an act at the Lilith Fair?
Says Frank on June 14, 2007
Ah, Frank, priceless. In all seriosuness, I once had Giardia, aka beaver fever. I got it in second grade. Up to that point I was chubby. After giardia, I was handsome and lean.
Says Anthony on June 14, 2007
ha ha ha
Says Andrew Sheffler on September 10, 2007
he he he
Says Daniel Martinez on September 10, 2007
This is funny ho ho ho ho ho hot hot hot hot ho ho ho ho sorry if i blew your potatoe
Says Me and myself on September 10, 2007
explosive diarreah...ewww
Says guest on February 15, 2008
yummy...explosive diahorea
Says magic turnip on April 30, 2008
sounds like an std
Says yuck fou on January 30, 2009