A 31 year old man became feverish 4 days after arriving at a vacation resort in Idaho. During his stay he ate at two restaurants that were not associated with the resort. AT the resort he drank soft drinks with ice, used the hot tub and went fishing. The resort is supplied by a well that was dug 3 years ago. He went to the hospital when he developed vomiting and bloody diarrhea. Gram-negative, lactose-negative bacteria were cultured from his stool. The patient recovered after receiving intravenous fluids. What microorganism most likely caused his symptoms? How is this disease transmitted? What is the most likely source of his infection and how would you verify the source?