Study design exercise, explanation needed

CASE 1. The Case of the Capri Tourist "Trots". The Italian Ministry of Public Health investigated an incident in the tourist district of Capri Island, Italy, which involved a gastrointestinal illness outbreak among a group of 22 U.S. tourists. The tourists who became ill reported that they had felt fine and then all of a sudden began feeling bad an average of 4.5 hours after eating near the central square in the city. Most of them reported multiple symptoms including stomach colics, diarrhea, nausea and vomiting or feelings of wanting to vomit. Their symptoms lasted an average of 26 hours. The national and international news media outlets picked up the story and caused a panic resulting in many calls to the mayor's office a dramatic drop in the number of tourists visiting downtown Capri and a loss of business in the same. After interviewing many people from the tour, epidemiologists from the Capri Dept. of Public Health identified "hand-crafted" tutti frutti gelato purchased from a single street vendor as the most likely source. They determined that virtually all the sick persons had ingested the gelato but that the 18 non-sick (well) people on the tour had rarely done so. . Your task: Based on the symptoms and putative vehicle: (1) identify the most likely cause of the illness (putative pathogen), (2) the study design that would have been used by the Italian epidemiologists to identify the source, and (3) the statistical methods they most likely used to analyze their data to confirm or reject their hypothesis. CASE 2. The Case of the Depressed Dentists. The epidemiological evidence suggests that U.S. dentists are at-risk for many stress-related physical and emotional conditions including back, neck, and hand pain, eye strain, marital problems, alcohol and drug addiction, depression and suicide. In addition, suicide rates among dentists is more than doubled that of the general population and close to three times greater than other white collar and professional workers. Epidemiologists at the American Dental Association (ADA) undertook a study to identify the factors associated with suicide in U.S. dentists. They used extant 2000-2010 data from a national U.S. Department of Labor database which contained data on occupational, sociodemographic, and other characteristics and merged it with files from a national mortality database maintained by the U.S. Department of Health and Human Services. . Your task: (1) Identify the study design