I'm afraid the emergency room docs in my town would not recognize a disease even if it was tattooed on the victim's forehead. Many ER docs are very focused on dealing with stabilizing trauma cases, drug overdoses and acute stuff like heart attacks. The offer top notch service on the common problems.
Large clusters of people with the same symptoms is likely the only way that a diagnostic process would go down a correct and consistent path...assuming the staff even recognizes a pattern of common symptoms within the set of patients waiting to be seen.