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noun, plural: zoonoses

An infectious disease that can be transmitted from an animal to a human host


Zoonosis is a disease of an animal that has the potential to be transmitted from an animal host to a human host. The transmission of the disease may occur directly or indirectly. Direct transmission of a zoonotic disease, for example, is when a dog with rabies transmits the disease to humans through a bite. Rabies is caused by a viral pathogen that is present in the nerves and the saliva of the infected animal. The virus enters the peripheral nervous system, and subsequently to the central nervous system of the human host where the virus causes damage to these organs. Another example of the direct transmission of a disease from an animal to the human host is the Ebola virus disease. The viral pathogen of Ebola infects primates and bats. Its spread to humans, though, is still unclear. It is presumed to have spread through direct contact with an infected animal (e.g. primates and monkeys) or with a fruit bat. Other zoonotic diseases that can be transmitted directly are HIV, taeniasis, balantidiasis, etc. Indirect transmission of a zoonotic disease is one in which the disease is spread via a vector. A vector is an intermediate species that serves as a pathogen-carrier but does not necessarily become infected with the pathogen.

Humans infecting animals is possible and is referred to as anthroponosis (sometimes called reverse zoonosis).1

Word origin: zoo- + Greek nósos' (“disease”)


  • zoonotic disease

See also:

Related form(s):

  • zoonotic (adjective, of, pertaining to, or relating to a zoonosis)

Mentioned in:

1 Messenger, A. M., Barnes, A.N., & Gray, G.C. (2014). "Reverse zoonotic disease transmission (zooanthroponosis): a systematic review of seldom-documented human biological threats to animals". PLoS ONE. 9 (2): e89055. doi:10.1371/journal.pone.0089055