Zoonotic diseases are diseases and infections that are naturally transmitted between vertebrate animals and humans. A zoonotic agent may be a bacterium, a virus, a fungus or other communicable disease agent. At least 61% of all human pathogens are zoonotic, and have represented at least 75% of all emerging pathogens during the past decade. On average five new human diseases appear every year, three of which are zoonotic and originate from animals.
Except for the newly emerging zoonoses such as Ebola Virus Disease, Middle East Respiratory Syndrome coronavirus (MERS-CoV), or highly pathogenic avian influenza such as H5N1, the vast majority are not prioritized by health systems at national and international levels.
FAO's animal health service is promoting efforts to identify the animals which serve as reservoirs or intermediate hosts of different zoonotic diseases, their geographic distribution, human and animal behaviors that favour transmission, as well as the mechanisms of disease transmission, and ecological and social factors that support or mitigate outbreaks.