Zoonotic disease

A zoonotic disease, or zoonosis, is a disease that can be passed from animals, whether wild or domesticated, to humans. Examples are brucellosis, rabies, HIV and influenza.

Around 150 zoonotic diseases are known to exist. Different diseases have different methods of transmission. In some cases, zoonotic diseases are transferred by contact with, or proximity to, infected animals. Here the zoonoses are analogous to contagious and infectious disease in human beings.

Other zoonotic diseases are spread by drinking water that contains the eggs of parasites. The eggs enter the water supply from the faeces of infected animals. Others are spread by eating the flesh of infected animals. Tapeworms and Salmonella are spread this way.

Yet others are spread by insect vectors. An insect, such as a flea, mosquito or tick, feeds on an infected animal, and then feeds on a human. In the process, the insect transfers the infecting organism. Malaria is transferred in that way.