John Snow’s investigation of cholera in 1854 London is consi…

John Snow’s investigation of cholera in 1854 London is considered a model for epidemiologic field investigations because it included a number of key aspects that informs much of modern epidemiology. The one aspect which was NOT RELEVANT in his investigations at that time was:

A number of passengers on a cruise ship from Puerto Rico to…

A number of passengers on a cruise ship from Puerto Rico to the Panama Canal have recently developed a gastrointestinal illness compatible with norovirus (formerly called Norwalk-like virus). Testing for norovirus is not readily available in any nearby island, and the test takes several days even where available. As the epidemiologist called on investigate the outbreak, you do not have facilities to confirm cases at hand for the moment. In this scenario, the best definition of a probable case would be: