Chronos, from Greek, means “time.” Chronic diseases are distinguished from acute diseases because they are drawn out over time. The sexually transmitted diseases (STDs) often have acute phases, but almost all of them have a chronic phase. Their acute phase often involves a lesion, pain, and inflammation near the site of entry a few days or a few weeks after the onset of infection. But STDs cause their worst damage at more distant sites as a result of their chronic presence. This continuum between acute and chronic disease among STDs reveals a surprising inconsistency in generalizations about disease causation. STDs, and a few other diseases, such as tuberculosis, that demonstrate this continuum, have led to the recognition that infectious diseases can be chronic. But when it comes to chronic diseases that do not have a distinct acute phase, infectious causation is often either dismissed or not even considered. Peptic ulcers, for example, do not have a distinct acute phase, and the infectious causation of ulcers was dismissed for a century in spite of supportive evidence.

A shocking realization arrives when we notice the general trend of which peptic ulcers are merely a specific example. All the diseases that were accepted as infectious during the last quarter of the nineteenth century were either entirely or largely acute—the diseases were obvious because sufferers had obvious symptoms just after they were infected—but all the human diseases that have been accepted as infectious during the past quarter century have been entirely or largely chronic. They are the stealth infections.

Knowing the reasons for this turnaround provides a sense of what the future holds in store, and how we can make that future more healthy. But to fully understand these reasons we need to be part psychologists and part medical historians.

*17\225\2*