Abstract
In the era of antibiotics and vaccines and prior to the appearance of AIDS, well-known infectious diseases received decreasing clinical attention. Occasionally, the opinion was also expressed that new types of infectious diseases could no longer be expected. However, a more detailed analysis of the state of infectious diseases yields quite a different picture. A variety of new infectious diseases has clinically been defined over the last few decades. New viruses, bacteria, and parasites with pathogenic potential for humans have been detected and well-known microorganisms have spread beyond their original geographic areas. Infectious agents, in particular viruses, permanently alter their genomes and may thus gain new clinical relevance. This article demonstrates that primarily the behavior of man influenced the nature and distribution of infectious diseases in the past and will affect the spread of infectious diseases in the future.