Last update:
07-Jul-2004

The distinction between infectious and chronic diseases is not always clear and these groups of diseases frequently overlap. Confusion between them became even greater when it was shown that some acute infections may not only become chronic but may also be associated with increased risk for other diseases characterized by different histological and clinical manifestations. The link between rheumatic fever and valvular heart disease and that of acute encephalitis with Parkinson’s disease are old paradigms of such an association. During the past two decades further evidence has accumulated from scientific research about the role of childhood infections in the development of chronic diseases later in life. In this article, a wide spectrum of chronic illnesses are reviewed for which the causative role of an infection earlier in life is either proven or strongly supported by scientific data. Epstein-Barr virus is well known as the cause of infectious mononucleosis; however, infection by this virus has been also associated with malignancies such as Burkitt’s lymphoma, nasopharyngeal carcinoma and Hodgkin’s disease. Helicobacter pylori infection has been recognized as the most common cause of peptic ulcer in adults and children. Infection by this microorganism is nowadays regarded as a strong risk factor for the development of gastric carcinoma. In addition to their relationship with neoplasms, bacterial and viral infections have been associated with the development of atherosclerosis. Several studies support the role of Chlamydia pneumoniae in atherogenesis and to a lesser degree that of other pathogens such as Helicobacter pylori, cytomegalovirus, and hepatitis A. Ongoing research will give clearer answers about the causative role of these pathogens in the near future. Finally, regarding the pathogenesis of certain chronic diseases such as bronchial asthma and childhood leukemia recent research has focused on the role of the delayed development of herd immunity. The protective effect of early exposure to common infections has been supported by these theories. The contribution of research conducted in Greece to the epidemiological investigation of childhood leukemia and its association with infections has been substantial.

Key words: Antecedent, Child, Chronic disease, Infection.