There are many kinds of contagious diseases which can afflict both human beings and animals (anthropozoonosis = diseases transmitted to humans by animals) and efforts to control them have in nearly all cases proved unsuccessful. Infections that can be passed on from domestic animals have become more virulent than in the past and therefore more dangerous. At the same time, concerning diseases transmitted from wild animals, research is progressing from an upstream perspective as we seek to establish global countermeasures.