[Evolution of viral diseases (author's transl)].

Biological characteristics of viruses determine their distribution in men and animals as well as their means of surviving or persisting. Taking measles as an example, we show that we are dealing with a recent phenomenon in evolution--as opposed, for instance, to those infections due to arboviruses (eg yellow fever) common in tropical regions. Survival rates are lower for highly virulent viruses (myxomatosis). Antigenmodification (influenza) or latency (herpes virus infections) allow the virus repeatedly to escape the body's immune system. The distribution and clinical appearance of the infections are influenced by environmental and particularly iatrogenic impact. Complete extirpation of infections will not be possible, only their manifestations will undergo continuous change.