Sometimes while traveling, people are infected with a protist parasite, giardia. one of the side effects of giardia infection is diarrhea. when someone has diarrhea, they lose excessive water and salt from the body. the result is loss of na+, dehydration that leads to decreased extracellular volume and plasma volume, and decreased arterial blood pressure. given this would the vasopressin secretion of a person infected with giardia: increasedecrease