Seems to me no one has an answer
Posted by: kayamedic on Dec-29-12 8:14 PM (EST)
to the original question, which was not about the need to filter water but rather is there a pattern of distribution of cryptospiridium and giardia.
I maintain there is from what amateur research I have been able to do. Whether or not I have had it is of less interest. (and I have from Mexico in unsanitary conditions, not on a trip)