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?

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?