Wars, famine and infectious diseases have endangered human progress and survival for centuries. The emergence of previously unknown infectious diseases have proved to
unfound the optimism that the fight against pathogens and the diseases they cause is over. Most „new“ infectious diseases that have affected humans over the past 30 years are known to be of zoonootic origin. The causes of their occurance are largely related to the intensification of human activity in the last
century. The increase in the impact of humanmade factors together with the ongoing evolution of viral and microbial variants suggests that new infectious diseases will continue to emerge. In addition to a modern effective monitoring system, biodiversity and protection of wildlife can play an important role in defending humans from emerging and re-emerging infectious diseases.
The aim of the article was to provide an overview of emerging and re-emerging infectious diseases, as well as to describe the epidemiological and ecological factors that affect their emergence.