Chronic diseases develop years or decades after the initial acute infection with immortal pathogens. Chronic infection can remain dormant and spread silently, can evolve into a chronic disease over time, and/or can erupt as a chronic or severe disease when triggered by new or repeated infections. It is difficult to identify the causes of chronic disease, because the scientific method prefers to report only findings and observations; studies are limited in time and do not extend for the duration of time needed for chronic disease to develop; and evidence of the cause may not be obvious when the chronic disease manifests itself years or decades after the acute infection.

Chronic disease evolves from chronic infection with immortal pathogens, the war between the pathogens and the immune system, and over time. Many immortal pathogens can cross the placenta, and infect a fetus in utero; and others are acquired during a lifetime. The longer a person has a chronic infection the more likely it will become a chronic disease. The younger the person when immortal pathogens are acquired, the earlier in life the disease can develop.

Children with birth defects and children hospitalized for pneumonia have a higher risk of cancer; and children exposed to the pathogens that cause Alzheimer’s at a young age or in utero may be at higher risk for early-onset Alzheimer’s. Testing newborns and testing the longest-living elderly patients, for immortal pathogens and parasites, to determine what they DO and DO NOT HAVE, could be enlightening, in the understanding of chronic diseases and aging.