A week after returning from a backpacking trip, four teenagers developed nausea and severe diarrhea. All had consumed untreated water from a stream which doctors concluded was infested with the organism, Giardia. Think about the symbiotic relationships that you studied in this unit. What type of relationship exists between the teens and the organism? So I am thinking that the Giardia is basically being a leech towards the human. It is using the human to get nutrients or food or whatever and it is not giving anything back in exchange. Would this be a parasitic relationship? Thanks