For an interesting article on living with Giardia, see
http://www.getlostmagazine.com/mcbee/2004/0404giardia/giardia.html

And several of the sites I have visited on Giardia & Crypto indicate that trouble can be caused by as little as one cyst. You can be treated multiple times, and still might have the cysts lying dormant, waiting for a nice, stressful period in your life to flare up again.

YUCK!

Sue