Just spoke with the microbiologist (PhD) at our lab and he has never heard of giardia in the bloodstream. It is a parasite which dwells in the GI tract and cannot be compared to something like Toxoplasmosis which does infect the blood and various internal tissues. He does not see how giardia could be transmitted into the breasts. Also, I believe that some research showed that breastmilk is very effective at killing giardia. Can't find the reference right now. Sharon Knorr Lactation Consultant Services Rochester, New York mailto:[log in to unmask]