Overview: F. H. Comhaire Many diseases were, at the beginning, merely defined by the description of their clinical appearance. Next, the pathogenic mechanisms underlying the diseases were recognized. Since then, the proof of presence of the pathogenic agent or agents has been required to confirm the diagnosis. However, it sometimes happens that the pathogenic agent can be demonstrated without the disease being clinically evident. Confusion arising from this observation may cause endless, often purely emotional discussions between "believers" and "non-believers". Moreover, if the disease involv
|