This essential presents infectious diseases of humans and animals that occur or can become endemic in Germany and Europe. These include current threats, African swine fever, avian influenza and COVID-19. In addition, the biology of mosquitoes is described. Globalisation and global warming favour the establishment of new mosquito species that can transmit viruses of the tropics and subtropics, e.g. chikungunya, dengue and West Nile virus. The Schmallenberg virus, which is of veterinary relevance, shows how rapidly new pathogens are spreading in Europe.