Although thermal scanners used in airports may detect travelers with symptoms, they are not effective since people exposed to an infectious disease could travel without any signs or symptoms and yet still be infectious.
Instead, researchers use these so-called natural-history studies to gain a better understanding of how the disease progresses without treatment and to track different symptoms.
Some gastroenterologists say that for every patient with celiac disease, they see six to eight who have the same symptoms, but without the tell-tale antibodies or intestinal damage needed to confirm celiac.