Actually Giardiasis epidemiology is interested in interactions that can happen between the different cycles that determine the environmental routes of transmission of this parasite to humans.
Giardiasis caused by Giardia lamblia is a zoonotic disease. It is not species specific and can transmitted from domesticated animals to humans especially childrens.
Man is the main reservoir of human giardiasis, animals constitute additional reservoirs of infection for humans including dogs,cats, guinea pigs,rats,mice and nonhuman primates.