Giardia may be the most common intestinal parasite in the US and one of the most common worldwide, but did you know it was only in the last 40 years that it was officially recognized as a human pathogen?! In today’s episode, we’ll travel back to a time before humans knew microbes even existed to discover alongside Leeuwenhoek a whole new world of animalcules like giardia. We’ll find out how seeing these critters for the first time changed everything, and how long it has taken to recognize their impact on the globe. Plus, we’ll tell you all about how giardia gives you such bad poops.